diff --git a/demo/smoke_led_strip_glow.mjs b/demo/smoke_led_strip_glow.mjs
index 94640573..9ae5f11e 100644
--- a/demo/smoke_led_strip_glow.mjs
+++ b/demo/smoke_led_strip_glow.mjs
@@ -347,6 +347,322 @@ check('static live_states:true + light_pools:true — source colour and the fiel
   JSON.stringify({ state: 'on', core: '#80d5ff', field: true, passive: true, badge: true }));
 check('a click on any static stripe toggles nothing', await evaluate(() => window.__card.hass.states['light.ceiling'].state), 'on');
 
+// #789 AC2: real transition events, not merely the declared CSS duration.
+// Do not read computed style/layout between insertion and its entering rAF:
+// that flush can manufacture the initial opacity and hide a lost fade.
+await page.emulateMedia({ reducedMotion: 'no-preference' });
+await evaluate(async () => {
+  const main = window.__card;
+  const host = document.createElement('div');
+  host.style.width = '700px'; document.body.appendChild(host);
+  const stat = document.createElement('houseplan-space-card');
+  stat.setConfig({ type: 'custom:houseplan-space-card', space: 'f1', light_pools: true, live_states: true });
+  stat.hass = main.hass; host.appendChild(stat);
+  await stat.updateComplete;
+  const proof = window.__ledFadeProof = {
+    cards: [main, stat], host, savedHass: main.hass, log: [], listeners: [],
+    selectors: ['[data-led-field="ceiling"]', '[data-glow-source="light.floor_lamp"]'],
+    parent: main.parentNode, next: main.nextSibling, updates: [0, 0], late: [], descriptors: [],
+  };
+  proof.nodes = () => proof.cards.map(card => proof.selectors.map(selector => card.shadowRoot.querySelector(selector)));
+  proof.set = async state => {
+    const states = { ...main.hass.states };
+    for (const eid of ['light.ceiling', 'light.floor_lamp']) states[eid] = { ...states[eid], state };
+    const hass = { ...main.hass, states };
+    for (const card of proof.cards) card.hass = hass;
+    await Promise.all(proof.cards.map(card => card.updateComplete));
+  };
+  for (const [cardIndex, card] of proof.cards.entries()) {
+    const listener = event => {
+      if (event.propertyName !== 'opacity') return;
+      const kind = proof.selectors.findIndex(selector => event.target.matches(selector));
+      if (kind >= 0) proof.log.push({ card: cardIndex, kind, event: event.type, elapsed: event.elapsedTime });
+    };
+    for (const name of ['transitionrun', 'transitionend']) card.shadowRoot.addEventListener(name, listener);
+    proof.listeners.push(listener);
+  }
+  await proof.set('off');
+});
+try {
+  await page.waitForFunction(() => window.__ledFadeProof.cards.every(card =>
+    card.shadowRoot.querySelector('[data-led-strip]')));
+  await page.waitForTimeout(650);
+  check('#789: both kinds start absent on both surfaces', await evaluate(() =>
+    window.__ledFadeProof.nodes().every(nodes => nodes.every(node => !node))), true);
+  const fadeSet = state => evaluate(async state => {
+    const proof = window.__ledFadeProof; proof.log = []; await proof.set(state);
+  }, state);
+  const fadeSnapshot = () => evaluate(() => {
+    const proof = window.__ledFadeProof;
+    return { log: proof.log, nodes: proof.nodes().map(nodes => nodes.map(node => node ? {
+      opacity: Number(getComputedStyle(node).opacity), leaving: node.classList.contains('is-leaving'),
+      entering: node.classList.contains('is-entering'),
+    } : null)) };
+  });
+  const checkFadeEvents = (phase, result, cards = [0, 1], kinds = [0, 1]) => {
+    for (const card of cards) for (const kind of kinds) {
+      const events = result.log.filter(event => event.card === card && event.kind === kind);
+      const label = `#789: ${card ? 'static' : 'main'} ${kind ? 'ordinary' : 'LED'} ${phase}`;
+      check(`${label} actually starts an opacity transition`, events.some(event => event.event === 'transitionrun'), true);
+      check(`${label} completes the unchanged 500 ms transition`, events.some(event =>
+        event.event === 'transitionend' && Math.abs(event.elapsed - 0.5) < 0.01), true);
+    }
+  };
+  await fadeSet('on');
+  await page.waitForTimeout(750);
+  const fadeOn = await fadeSnapshot();
+  checkFadeEvents('on', fadeOn);
+  check('#789: all four fields finish on at full opacity', fadeOn.nodes.every(nodes =>
+    nodes.every(node => node?.opacity === 1 && !node.leaving)), true);
+  // Observe the real bundled call graph, without wrapping private methods or
+  // inferring render-pass wiring from source text. Coverage is not timing data.
+  const coverageSession = await page.context().newCDPSession(page);
+  try {
+    await coverageSession.send('Profiler.enable');
+    await coverageSession.send('Profiler.startPreciseCoverage', { callCount: true, detailed: true });
+    for (const pass of [1, 2]) {
+      await coverageSession.send('Profiler.takePreciseCoverage');
+      await evaluate(async () => {
+        const card = window.__card;
+        card.requestUpdate();
+        for (let attempt = 0; attempt < 10; attempt++) {
+          const complete = await card.updateComplete;
+          if (complete !== false && !card.isUpdatePending) return;
+        }
+        throw new Error('#789: observed main render did not settle');
+      });
+      const result = await coverageSession.send('Profiler.takePreciseCoverage');
+      const functions = result.result.flatMap(script => script.functions);
+      const calls = name => functions.filter(fn => fn.functionName === name)
+        .reduce((sum, fn) => sum + (fn.ranges[0]?.count || 0), 0);
+      const counts = { render: calls('_renderLightPass'), reads: calls('_lightBarriers'), builds: calls('_resolveLightBarriers') };
+      check(`#789: observed main render pass ${pass} executes`, counts.render > 0, true);
+      check(`#789: Glow and LED share barrier reads in pass ${pass}`, counts.reads >= 2 * counts.render, true);
+      check(`#789: pass ${pass} resolves barriers exactly once per render, never across renders`, counts.builds, counts.render);
+      console.log('#789 render-pass coverage', JSON.stringify({ pass, ...counts }));
+    }
+  } finally {
+    await coverageSession.send('Profiler.stopPreciseCoverage');
+    await coverageSession.send('Profiler.disable');
+    await coverageSession.detach();
+  }
+  await fadeSet('off');
+  check('#789: normal off retains all four nodes for their fade', await evaluate(() =>
+    window.__ledFadeProof.nodes().every(nodes => nodes.every(node => node?.classList.contains('is-leaving')))), true);
+  await page.waitForTimeout(750);
+  const fadeOff = await fadeSnapshot();
+  checkFadeEvents('off', fadeOff);
+  check('#789: normal off removes all four fields after fading', fadeOff.nodes.every(nodes => nodes.every(node => !node)), true);
+
+  await page.emulateMedia({ reducedMotion: 'reduce' });
+  await fadeSet('on');
+  await page.waitForTimeout(200);
+  const reducedOn = await fadeSnapshot();
+  check('#789: reduced motion shows LED and ordinary immediately on both surfaces', reducedOn.nodes.every(nodes =>
+    nodes.every(node => node?.opacity === 1)), true);
+  check('#789: reduced on starts no CSS opacity animation', reducedOn.log.length, 0);
+  await fadeSet('off');
+  await page.waitForTimeout(200);
+  const reducedOff = await fadeSnapshot();
+  check('#789: reduced off is immediately dark on both surfaces', reducedOff.nodes.every(nodes =>
+    nodes.every(node => node?.opacity === 0)), true);
+  check('#789: reduced off starts no CSS opacity animation', reducedOff.log.length, 0);
+  await page.waitForTimeout(450);
+  check('#789: reduced off still removes every field', await evaluate(() =>
+    window.__ledFadeProof.nodes().every(nodes => nodes.every(node => !node))), true);
+
+  await page.emulateMedia({ reducedMotion: 'no-preference' });
+  await fadeSet('on');
+  await page.waitForTimeout(750);
+  await evaluate(() => { window.__ledFadeProof.savedNodes = window.__ledFadeProof.nodes(); });
+  await fadeSet('off');
+  await page.waitForTimeout(100);
+  await fadeSet('on');
+  await page.waitForTimeout(750); // beyond the cancelled off timer as well as the returning fade
+  check('#789: rapid off/on retains every DOM node beyond the stale fade deadline', await evaluate(() => {
+    const proof = window.__ledFadeProof;
+    return proof.nodes().every((nodes, card) => nodes.every((node, kind) => node
+      && node === proof.savedNodes[card][kind] && !node.classList.contains('is-leaving')
+      && Number(getComputedStyle(node).opacity) === 1));
+  }), true);
+
+  await fadeSet('off');
+  await page.waitForTimeout(650);
+  await evaluate(async () => {
+    // Both Lit commits finish in microtasks, before a browser entering-frame.
+    await window.__ledFadeProof.set('on'); await window.__ledFadeProof.set('off');
+  });
+  await page.waitForTimeout(650);
+  check('#789: off before the entry frame cannot resurrect a field', await evaluate(() =>
+    window.__ledFadeProof.nodes().every(nodes => nodes.every(node => !node))), true);
+
+  await evaluate(async () => {
+    const proof = window.__ledFadeProof;
+    await proof.set('on');
+    // Lit's updated() can enqueue a header/summary follow-up. Drain only its
+    // microtasks before observing disconnect: entry rAFs must still be pending.
+    const drainUpdates = async phase => {
+      for (let attempt = 0; attempt < 10; attempt++) {
+        const complete = await Promise.all(proof.cards.map(card => card.updateComplete));
+        if (complete.every(result => result !== false) && proof.cards.every(card => !card.isUpdatePending)) return;
+      }
+      throw new Error(`#789: pending Lit microtasks did not settle ${phase} disconnect`);
+    };
+    await drainUpdates('before');
+    if (!proof.nodes().every(nodes => nodes.every(node => node?.classList.contains('is-entering')))) {
+      throw new Error('#789: disconnect witness must precede every entering frame');
+    }
+    for (const [index, card] of proof.cards.entries()) {
+      proof.descriptors[index] = Object.getOwnPropertyDescriptor(card, 'requestUpdate');
+      const original = card.requestUpdate;
+      card.requestUpdate = function (...args) {
+        proof.updates[index]++;
+        if (!this.isConnected) proof.late.push({ card: index, stack: new Error().stack });
+        return original.apply(this, args);
+      };
+    }
+    // Disconnect in this microtask, with entry rAFs/feather timers still pending.
+    for (const card of proof.cards) card.remove();
+    // Teardown itself mutates reactive header/summary state. Finish that same
+    // microtask chain before measuring late callbacks; no rAF/timer can run yet.
+    await drainUpdates('after');
+    proof.updates = [0, 0];
+    proof.late = [];
+  });
+  await page.waitForTimeout(750);
+  check('#789: disconnected main/static owners receive no late transition updates', await evaluate(() =>
+    window.__ledFadeProof.updates), [0, 0]);
+  const late = await evaluate(() => window.__ledFadeProof.late);
+  if (late.length) console.log('#789 late update diagnostic', JSON.stringify(late, null, 2));
+  await evaluate(async () => {
+    const proof = window.__ledFadeProof; proof.log = [];
+    proof.parent.insertBefore(proof.cards[0], proof.next?.parentNode === proof.parent ? proof.next : null);
+    proof.host.appendChild(proof.cards[1]);
+    await Promise.all(proof.cards.map(card => card.updateComplete));
+  });
+  await page.waitForTimeout(750);
+  const reconnected = await fadeSnapshot();
+  checkFadeEvents('reconnected', reconnected);
+  check('#789: reconnect starts clean lifecycles and returns all four fields', reconnected.nodes.every(nodes =>
+    nodes.every(node => node?.opacity === 1 && !node.leaving)), true);
+  for (const exit of [
+    { label: 'disabled pools', config: { space: 'f1', light_pools: false } },
+    { label: 'another space', config: { space: 'garden', light_pools: true } },
+  ]) {
+    await fadeSet('off');
+    await page.waitForTimeout(650);
+    await evaluate(async config => {
+      const proof = window.__ledFadeProof;
+      await proof.set('on');
+      if (!proof.nodes()[1].every(node => node?.classList.contains('is-entering'))) {
+        throw new Error('#789: config exit must precede the static entering frame');
+      }
+      proof.cards[1].setConfig({ type: 'custom:houseplan-space-card', live_states: true, ...config });
+      await proof.cards[1].updateComplete;
+    }, exit.config);
+    await page.waitForTimeout(750);
+    check(`#789: ${exit.label} removes previous static fields beyond their old callbacks`, await evaluate(() =>
+      window.__ledFadeProof.nodes()[1].every(node => !node)), true);
+    await evaluate(async () => {
+      const proof = window.__ledFadeProof; proof.log = [];
+      proof.cards[1].setConfig({ type: 'custom:houseplan-space-card', space: 'f1', light_pools: true, live_states: true });
+      await proof.cards[1].updateComplete;
+    });
+    await page.waitForTimeout(750);
+    const returned = await fadeSnapshot();
+    checkFadeEvents(`return from ${exit.label}`, returned, [1]);
+    check(`#789: return from ${exit.label} starts fresh static fields`, returned.nodes[1].every(node =>
+      node?.opacity === 1 && !node.leaving), true);
+  }
+  await fadeSet('off');
+  await page.waitForTimeout(650);
+  await evaluate(async () => {
+    const proof = window.__ledFadeProof;
+    await proof.set('on');
+    if (!proof.nodes()[0].every(node => node?.classList.contains('is-entering'))) {
+      throw new Error('#789: main navigation must start before the entering frame');
+    }
+    await window.__hpTest.switchSpace('garden');
+  });
+  await page.waitForTimeout(750);
+  check('#789: main LED-to-empty navigation removes both former sources beyond stale callbacks', await evaluate(() =>
+    window.__ledFadeProof.nodes()[0].every(node => !node)), true);
+  await evaluate(async () => {
+    window.__ledFadeProof.log = [];
+    await window.__hpTest.switchSpace('f1');
+  });
+  await page.waitForTimeout(750);
+  const mainReturned = await fadeSnapshot();
+  checkFadeEvents('return from LED-free space', mainReturned, [0], [0]);
+  // Main ordinary Glow has retained its per-space appearance without replay on
+  // navigation since before #789. Preserve that UX; only LED starts a fresh
+  // lifecycle here. The real on/off fade assertions above still cover both.
+  check('#789: main navigation back restores the LED field at full opacity',
+    mainReturned.nodes[0][0]?.opacity === 1 && !mainReturned.nodes[0][0].leaving, true);
+  const retainedOrdinary = mainReturned.nodes[0][1];
+  check('#789: main navigation preserves steady ordinary Glow without replay',
+    retainedOrdinary?.opacity === 1 && !retainedOrdinary.entering && !retainedOrdinary.leaving, true);
+
+  // Keep the same mounted static card while its server-side space vanishes.
+  // This exercises renderSpaceStatic's !space exit, not setConfig/disconnect.
+  await fadeSet('off');
+  await page.waitForTimeout(650);
+  await evaluate(async () => {
+    const proof = window.__ledFadeProof;
+    await proof.set('on');
+    if (!proof.nodes()[1].every(node => node?.classList.contains('is-entering'))) {
+      throw new Error('#789: server removal must start before the static entering frame');
+    }
+    await window.__hpTest.setServerConfig(cfg => {
+      proof.savedConfig = structuredClone(cfg);
+      cfg.spaces = cfg.spaces.filter(space => space.id !== 'f1');
+      cfg.markers = (cfg.markers || []).filter(marker => marker.space !== 'f1');
+    });
+  });
+  await page.waitForFunction(() => !window.__ledFadeProof.cards[1].shadowRoot.querySelector('[data-led-strip]'));
+  await page.waitForTimeout(750);
+  check('#789: a missing server space clears both fields without disconnecting the static card', await evaluate(() => {
+    const proof = window.__ledFadeProof;
+    return proof.cards[1].isConnected && proof.nodes()[1].every(node => !node);
+  }), true);
+  await evaluate(async () => {
+    const proof = window.__ledFadeProof; proof.log = [];
+    await window.__hpTest.setServerConfig(proof.savedConfig);
+    delete proof.savedConfig;
+  });
+  await page.waitForTimeout(750);
+  const restoredSpace = await fadeSnapshot();
+  checkFadeEvents('restored server space', restoredSpace, [1]);
+  check('#789: restoring a server space starts fresh static LED and ordinary fields', restoredSpace.nodes[1].every(node =>
+    node?.opacity === 1 && !node.leaving), true);
+  await evaluate(() => window.__hpTest.switchSpace('f1'));
+  await page.waitForTimeout(750);
+} finally {
+  await page.emulateMedia({ reducedMotion: 'no-preference' });
+  await evaluate(async () => {
+    const proof = window.__ledFadeProof;
+    if (proof.savedConfig) {
+      await window.__hpTest.setServerConfig(proof.savedConfig);
+      delete proof.savedConfig;
+    }
+    for (const [index, card] of proof.cards.entries()) {
+      for (const name of ['transitionrun', 'transitionend']) card.shadowRoot.removeEventListener(name, proof.listeners[index]);
+      if (index < proof.descriptors.length) {
+        if (proof.descriptors[index]) Object.defineProperty(card, 'requestUpdate', proof.descriptors[index]);
+        else delete card.requestUpdate;
+      }
+    }
+    const main = proof.cards[0];
+    if (!main.isConnected) proof.parent.insertBefore(main, proof.next?.parentNode === proof.parent ? proof.next : null);
+    main.hass = proof.savedHass;
+    proof.cards[1].remove(); proof.host.remove();
+    delete window.__ledFadeProof;
+    await main.updateComplete;
+  });
+  await page.waitForFunction(() => window.__card.shadowRoot.querySelector('[data-led-strip]'));
+  await settle();
+}
+
 for (const mode of ['plan', 'decor']) {
   await evaluate(mode => window.__hpTest.setMode(mode), mode);
   check(`#790: ${mode} keeps the coloured core passive and translucent`, await evaluate(() => {
@@ -401,4 +717,65 @@ check('the press loads the tool and draws for the same marker', await evaluate((
   return !!led?.tool && led.chain?.convert === 'd_tv' && !window.__card._markerDialog;
 }));
 
+// A fresh document makes both lazy imports genuinely cold. Hold each network
+// response, disconnect its requesting static card, then let the actual module
+// finish loading: no private runtime hooks or synthetic callback.
+await evaluate(() => localStorage.clear()); // isolated demo browser storage only
+ledRequests.length = 0;
+await page.reload();
+await page.waitForFunction(() => window.__card?._loadOk);
+await installHpTestOnPage(page);
+await evaluate(async () => {
+  window.__card.setConfig({ type: 'custom:houseplan-card', floor: 'garden' });
+  await window.__card.updateComplete;
+});
+await setStrips(ceilingStrip, { glow_enabled: true });
+check('#789: fixed non-LED main card leaves both LED imports cold', ledRequests.filter(url =>
+  /^led-strip-(runtime|field)-/.test(url)).length, 0);
+for (const kind of ['runtime', 'field']) {
+  let releaseImport;
+  const barrier = new Promise(resolve => { releaseImport = resolve; });
+  const pattern = new RegExp(`/led-strip-${kind}-[^/]+\\.js(?:\\?.*)?$`);
+  const holdImport = async route => { await barrier; await route.fallback(); };
+  await page.route(pattern, holdImport);
+  try {
+    const requested = page.waitForRequest(pattern);
+    await evaluate(async () => {
+      const card = document.createElement('houseplan-space-card');
+      card.setConfig({ type: 'custom:houseplan-space-card', space: 'f1', light_pools: true, live_states: true });
+      card.hass = window.__card.hass;
+      document.body.appendChild(card);
+      window.__ledColdProof = { card, updates: 0, original: card.requestUpdate };
+      await card.updateComplete;
+    });
+    await requested;
+    check(`#789: cold static ${kind} import has not painted its content yet`, await evaluate(kind =>
+      !window.__ledColdProof.card.shadowRoot.querySelector(kind === 'runtime' ? '[data-led-strip]' : '[data-led-field]'), kind), true);
+    await evaluate(async () => {
+      const proof = window.__ledColdProof, card = proof.card;
+      card.remove();
+      let settled = false;
+      for (let attempt = 0; attempt < 10; attempt++) {
+        const complete = await card.updateComplete;
+        if (complete !== false && !card.isUpdatePending) { settled = true; break; }
+      }
+      if (!settled) throw new Error('#789: cold static teardown did not settle');
+      card.requestUpdate = function (...args) { proof.updates++; return proof.original.apply(this, args); };
+    });
+    const arrived = page.waitForResponse(pattern);
+    releaseImport();
+    await (await arrived).finished();
+    await page.waitForTimeout(750);
+    check(`#789: a cold ${kind} arriving after static disconnect requests no update`, await evaluate(() =>
+      window.__ledColdProof.updates), 0);
+  } finally {
+    releaseImport();
+    await page.unroute(pattern, holdImport);
+    await evaluate(() => {
+      const proof = window.__ledColdProof;
+      if (proof) { delete proof.card.requestUpdate; proof.card.remove(); delete window.__ledColdProof; }
+    });
+  }
+}
+
 await finish(browser);
diff --git a/docs/ARCHITECTURE.md b/docs/ARCHITECTURE.md
index a337d4ce..f45088e7 100644
--- a/docs/ARCHITECTURE.md
+++ b/docs/ARCHITECTURE.md
@@ -520,7 +520,10 @@ ignores `#space=`.
   visual layer with one selection/transform/history pipeline; image bytes live
   only in the asset store: [DECOR-EDITOR](DECOR-EDITOR.md), [FURNITURE](FURNITURE.md).
 - **Light and Glow** — one visibility region per source (#71); Glow is an overlay
-  independent of the data fill (#55): [LIGHT](LIGHT.md). **Room fill** —
+  independent of the data fill (#55): [LIGHT](LIGHT.md). Shared source entry
+  scheduling is owner-local; `LightBarrierPass` shares revisions only inside
+  the main card's synchronous render, never across subsequent edits (#789).
+  **Room fill** —
   `resolveEffectiveRoomFill()` is the single projection for room floors,
   clean-floor holes and opening tunnels; `room_color` styles only borders and
   names; custom colour and legacy tokens (#56, #581):
diff --git a/docs/CHANGELOG.md b/docs/CHANGELOG.md
index 1123c0e0..8c4bcff2 100644
--- a/docs/CHANGELOG.md
+++ b/docs/CHANGELOG.md
@@ -2,6 +2,11 @@
 
 ## Unreleased
 
+- Removed redundant card updates when many lights appear together and repeated
+  light-barrier calculations within a frame; the light geometry and fades are
+  unchanged. Pending LED updates are also cleared when leaving their space or
+  disconnecting a card ([#789](https://github.com/Matysh/houseplan-card/issues/789)).
+
 - An on LED strip now shows its light colour inside the outline even when
   Glow is enabled; off strips stay white
   ([#790](https://github.com/Matysh/houseplan-card/issues/790)).
diff --git a/docs/CHANGELOG.ru.md b/docs/CHANGELOG.ru.md
index 1bbb19e0..7fabcb75 100755
--- a/docs/CHANGELOG.ru.md
+++ b/docs/CHANGELOG.ru.md
@@ -8,6 +8,12 @@
 
 ## Не выпущено
 
+- Убраны лишние обновления карточки при одновременном появлении множества
+  источников света и повторные расчёты препятствий в одном кадре. Форма света
+  и плавность переходов сохранены. Отложенные обновления LED также очищаются
+  при уходе с пространства или отключении карточки
+  ([#789](https://github.com/Matysh/houseplan-card/issues/789)).
+
 - Ядро включённой LED-ленты внутри обводки теперь показывает цвет её свечения
   и при включённом Glow; выключенная лента остаётся белой
   ([#790](https://github.com/Matysh/houseplan-card/issues/790)).
diff --git a/docs/DEVELOPMENT.md b/docs/DEVELOPMENT.md
index 519cb157..bf87dabc 100644
--- a/docs/DEVELOPMENT.md
+++ b/docs/DEVELOPMENT.md
@@ -183,6 +183,15 @@ new `size-pack` with 467.63 MiB; the accepted upper bound is 487.63 MiB.
 
 - Frontend: `npm test` — compiles src/logic.ts+rules.ts (tsconfig.test.json) and runs node:test
   (test/*.test.mjs). Strict typing: `npm run typecheck` (tsc --noEmit, part of `npm run build`).
+- Shared Glow scheduling and render-local barrier reuse (#789) have separate
+  scheduler/memo unit witnesses. `smoke_led_strip_glow` observes real opacity
+  transition events on main/static LED and ordinary pools, without a forced
+  style read between insertion and the entering frame. A declared 500 ms CSS
+  duration alone is not evidence that a fade actually runs. Main-card ordinary
+  Glow retains its previous no-replay behavior on return to a visited space;
+  that navigation witness checks its steady state, not a newly invented fade.
+  The complete
+  `led-strips-v1` performance gate remains separate from these correctness checks.
 - Pure backend on native Windows (with no HA plugin autoload): use the explicit
   `python -Arguments @(...)` invocation above after setting
   `$env:PYTEST_DISABLE_PLUGIN_AUTOLOAD='1'`.
diff --git a/docs/LIGHT.md b/docs/LIGHT.md
index 6ab6d043..953247a1 100644
--- a/docs/LIGHT.md
+++ b/docs/LIGHT.md
@@ -429,6 +429,23 @@ only the geometry differs:
   luminance bands of the shared `GLOW_FALLOFF` in one mask, so corners and the
   closing of a loop neither seam nor double the brightness. Intensity and the 500 ms fade
   are the shared `glowAlpha` / `GLOW_FADE_MS`.
+- **Scheduling.** Sources first seen by one synchronous render share one
+  entering-frame callback per owner/runtime, not one complete update per
+  source (#789). A microtask seals the batch so a later rAF cannot bring a
+  newly inserted source into an earlier entry frame. Forget/disconnect cancels
+  empty batches; identity checks reject late callbacks. Normal 500 ms fade and
+  reduced-motion behavior remain shared with ordinary Glow.
+- **Render-local scene reuse.** The main card shares a resolved barrier scene
+  between its Glow/LED consumers within one synchronous `render()` only
+  (`LightBarrierPass`). `finally` clears the memo even on early return or error.
+  The next render, callbacks and handlers still resolve the content-based
+  revision; this is not a cross-frame cache keyed only by object identity.
+- **Owner teardown.** Main and static cards release LED state when their next
+  space has no visible strips, not only when another field renders. The static
+  card also releases it on disconnect, space change or disabling light pools;
+  switching off live states releases the field while retaining the neutral tube.
+  Both lazy runtime and field readiness callbacks check the actual owner's
+  connection before requesting an update. Reconnect creates a fresh lifecycle.
 - **Visibility.** Classify and sample the full polyline at radius/4 or finer,
   retaining every actual vertex and both ends; never thin a short final run
   or an acute corner. The continuous field is clipped to the union of the
diff --git a/docs/STATUS.md b/docs/STATUS.md
index 469f0609..e0710595 100644
--- a/docs/STATUS.md
+++ b/docs/STATUS.md
@@ -31,6 +31,7 @@ Everything computable from the tree and git; regenerate, never edit by hand
 | Branches | `main` carries stable releases only; pre-release tags point at `dev`. Work lands on `dev`, which is equal to or ahead of `main`, never behind. |
 | LED regression acceptance | #788 covers mixed face/free and fractional-coordinate joins, winding-safe field unions, retained endpoints/acute vertices and circle–wall transition events. The actual owner export is exercised locally; public fixtures are synthetic. Pixel oracles, not just SVG counts, protect the visible falloff. |
 | LED core colour | #790 makes the on core follow the resolved light colour with or without Glow. Off, unavailable and non-live static strips keep their neutral presentation; geometry and field brightness are unchanged. |
+| LED performance work | #789 batches entering callbacks per owner and reuses light-barrier revisions within one synchronous render. No change to bands, emitters, clips or raster precision. The complete 50×50 performance acceptance remains mandatory; these structural changes alone do not certify the camera budget. |
 | Warm remount | Delayed editor restoration preserves the original View camera, reserves pending chrome space, and yields synchronously to mode/space navigation (#762). Header/stage dimensions are published as one settled pair. Canonical: `docs/WARM-REMOUNT.md`. |
 | 2.5D View | Public since #649: the installation-wide General settings switch `settings.volumetric_view` (Display). Flat stays the default and byte-for-byte unchanged; editors and `houseplan-space-card` stay Flat. Canonical: `docs/ISOMETRIC.md`. |
 | Input support | Owner's rule since 2026-08-08: View and kiosk are fully supported and release-blocking on touch; the three editors are desktop-first, touch editing is best effort. Canonical: `docs/TOUCH-SUPPORT.md`. |
diff --git a/docs/testing-notes/mutation-browser-guards.md b/docs/testing-notes/mutation-browser-guards.md
index 21656911..e32cef7a 100644
--- a/docs/testing-notes/mutation-browser-guards.md
+++ b/docs/testing-notes/mutation-browser-guards.md
@@ -14,11 +14,11 @@ to prove that the Node witness actually kills it.
 | --- | ---: | --- |
 | Performance threshold | 4 | The witness measures real browser wall-time or frame work; a pure assertion cannot prove the budget. |
 | Browser harness integrity | 4 | The mutation breaks page-error, round-trip or page-registration observation in the browser harness itself. |
-| Paint, cascade and layer composition | 36 | The invariant depends on computed CSS, SVG paint, clipping, stacking or pixels produced by Chromium. |
+| Paint, cascade and layer composition | 37 | The invariant depends on computed CSS, SVG paint, clipping, stacking or pixels produced by Chromium. |
 | Pointer geometry and trusted interaction | 47 | The invariant depends on hit testing, pointer capture, touch/keyboard dispatch or live DOM geometry. |
 | Responsive DOM layout | 38 | The invariant depends on measured element boxes, responsive breakpoints, native/HA dialog shells or focusable target size. |
-| Custom-element and HA browser lifecycle | 101 | The invariant crosses Lit/custom-element lifecycle, browser storage/events, lazy loading or a complete HA-card state transition. |
-| **Total** | **230 / 200** | Above the guideline `mutation-gate --check` warns rather than fails (#699); each guard above it is held by its own reason in this inventory and its `because`. |
+| Custom-element and HA browser lifecycle | 103 | The invariant crosses Lit/custom-element lifecycle, browser storage/events, lazy loading or a complete HA-card state transition. |
+| **Total** | **233 / 200** | Above the guideline `mutation-gate --check` warns rather than fails (#699); each guard above it is held by its own reason in this inventory and its `because`. |
 
 ## Measured effect
 
@@ -81,6 +81,7 @@ The invariant depends on computed CSS, SVG paint, clipping, stacking or pixels p
 - `device-keyboard-bypasses-click-path`
 - `device-long-value-ellipsis-restored`
 - `device-unavailable-hover-restored`
+- `glow-entry-initial-opacity-skipped`
 - `golden-filled-tunnel-removed`
 - `golden-lamp-out-of-reach`
 - `hatch-static-renderer-untouched`
@@ -250,6 +251,8 @@ The invariant crosses Lit/custom-element lifecycle, browser storage/events, lazy
 - `floor-geometry-key-global-epoch`
 - `floor-geometry-key-ignores-content`
 - `french-locale-wrong-dictionary`
+- `glow-barrier-render-pass-wiring-skipped`
+- `glow-static-led-release-skipped`
 - `household-enter-stops-acting`
 - `household-marker-drops-keyboard-reach`
 - `hp-dialog-escape-does-not-close`
diff --git a/scripts/mutation-registry.mjs b/scripts/mutation-registry.mjs
index af3b6fa2..33fc4ec8 100644
--- a/scripts/mutation-registry.mjs
+++ b/scripts/mutation-registry.mjs
@@ -7387,7 +7387,7 @@ const MUTANT_DEFINITIONS = [
       find: '        ${passageGlowTunnels}\n'
         + '        <g class="decorlayer" pointer-events="none">${decorImages}</g>\n'
         + '        <g class="hp-stairs-layer" pointer-events="none">${stairShapes}</g>\n'
-        + '        ${glowPools}\n        ${ledVisible(',
+        + '        ${glowPools}\n        ${showLed ?',
       replace: '        ${passageGlowTunnels}\n'
         + '        ${!space.bg && !disp.showNames ? svg`<g class="room-svg-labels" pointer-events="none">${space.rooms.map((room) => {\n'
         + '          const center = roomCenter(room);\n'
@@ -7397,7 +7397,7 @@ const MUTANT_DEFINITIONS = [
         + '        <g class="decorlayer" pointer-events="none">${decorImages}</g>\n'
         + '        <g class="hp-stairs-layer" pointer-events="none">${stairShapes}</g>\n'
         + '        ${glowPools}\n'
-        + '        ${ledVisible(',
+        + '        ${showLed ?',
     }],
   },
   {
@@ -14234,6 +14234,61 @@ const MUTANT_DEFINITIONS = [
       replace: "    ? body.slice(0, at).replace(/\\s+$/, '')",
     }],
   },
+  {
+    id: 'glow-barrier-render-pass-wiring-skipped',
+    guard: 'node demo/smoke_led_strip_glow.mjs',
+    because: '#789 AC4: precise coverage of the real main-card Glow plus LED render must resolve barriers '
+      + 'once per pass; only this bundled custom-element path proves the pass cache is actually wired to its consumers',
+    patches: [{
+      file: 'src/houseplan-card.ts',
+      find: '    return this._lightBarrierPass.read(space, () => this._resolveLightBarriers(space));',
+      replace: '    return this._resolveLightBarriers(space);',
+    }],
+  },
+  {
+    id: 'glow-barrier-render-pass-reuse-skipped',
+    guard: 'node --test test/light-barrier-pass.test.mjs',
+    because: '#789 AC4: a synchronous render pass must fingerprint/build each space once while still '
+      + 'invalidating across passes; disabling its local read cache repeats expensive work without changing pixels',
+    patches: [{
+      file: 'src/glow-scene.ts',
+      find: '    const retained = this.scenes?.get(space);',
+      replace: '    const retained = undefined;',
+    }],
+  },
+  {
+    id: 'glow-entry-initial-opacity-skipped',
+    guard: 'node demo/smoke_led_strip_glow.mjs',
+    because: '#789 AC2: only browser CSS paint and real opacity transitionrun/transitionend events '
+      + 'prove that LED and ordinary pools on both surfaces paint their initial entering frame without a forced style flush',
+    patches: [{
+      file: 'src/glow-scene.ts',
+      find: '      state.enteringSources.add(key);',
+      replace: '      // mutant: render the new source fully visible before its entry frame',
+    }],
+  },
+  {
+    id: 'glow-static-led-release-skipped',
+    guard: 'node demo/smoke_led_strip_glow.mjs',
+    because: '#789 AC4: disconnecting and reconnecting the actual static custom element must start a fresh '
+      + 'LED entering transition; a host connection guard alone cannot release the retained field lifecycle',
+    patches: [{
+      file: 'src/space-card.ts',
+      find: '    ledRelease(this._glowRuntimeState);\n    this._continuityHistory =',
+      replace: '    // mutant: retain the static LED field lifecycle across disconnect\n    this._continuityHistory =',
+    }],
+  },
+  {
+    id: 'glow-entry-per-source-frame',
+    guard: 'node --test test/glow-entry-batch.test.mjs',
+    because: '#789 AC1: the controlled scheduler must see one frame and one update for 50 simultaneous '
+      + 'sources; disabling batch reuse restores the former linear callback fan-out without needing a browser',
+    patches: [{
+      file: 'src/glow-scene.ts',
+      find: '  let batch = state.collectingEntryBatch;',
+      replace: '  let batch: GlowEntryBatch | null = null;',
+    }],
+  },
   {
     id: 'led-icon-not-suppressed',
     guard: 'node demo/smoke_led_strip_glow.mjs',
diff --git a/src/glow-scene.ts b/src/glow-scene.ts
index 1476f928..791ccc68 100644
--- a/src/glow-scene.ts
+++ b/src/glow-scene.ts
@@ -88,6 +88,31 @@ export interface LightBarrierScene {
   opaqueBodies: number[][][];
 }
 
+/**
+ * One synchronous render reads the same scene for ordinary Glow and LED.
+ * Share that read, including its content fingerprint, only inside the render.
+ * Handlers, subsequent renders and exception paths never retain the memo:
+ * in-place edits and changed opening states must still rebuild the revision.
+ */
+export class LightBarrierPass {
+  private scenes: Map<SpaceModel, LightBarrierScene> | null = null;
+
+  run<T>(render: () => T): T {
+    const previous = this.scenes;
+    this.scenes = new Map();
+    try { return render(); }
+    finally { this.scenes.clear(); this.scenes = previous; }
+  }
+
+  read(space: SpaceModel, build: () => LightBarrierScene): LightBarrierScene {
+    const retained = this.scenes?.get(space);
+    if (retained) return retained;
+    const scene = build();
+    this.scenes?.set(space, scene);
+    return scene;
+  }
+}
+
 export interface LightZeroWalls {
   contour: number[][];
   barriers: number[][];
@@ -101,6 +126,8 @@ export interface GlowRuntimeHost {
   reducedMotion: () => boolean;
 }
 
+type GlowEntryBatch = { keys: Set<string>; raf: number };
+
 export interface GlowRuntimeState {
   clipCache: Map<string, GlowClipGeometry | null>;
   geometryWarnings: Set<string>;
@@ -108,7 +135,8 @@ export interface GlowRuntimeState {
   renderedSources: Map<string, number>;
   lastAppearance: Map<string, { c: string; alpha: number }>;
   enteringSources: Set<string>;
-  enterRafs: Map<string, number>;
+  enterBatches: Set<GlowEntryBatch>;
+  collectingEntryBatch: GlowEntryBatch | null;
   fadeTimers: Map<string, number>;
   featherSuspendUntil: number;
   featherResumeTimer: number;
@@ -129,7 +157,8 @@ export function createGlowRuntimeState(): GlowRuntimeState {
     renderedSources: new Map(),
     lastAppearance: new Map(),
     enteringSources: new Set(),
-    enterRafs: new Map(),
+    enterBatches: new Set(),
+    collectingEntryBatch: null,
     fadeTimers: new Map(),
     featherSuspendUntil: 0,
     featherResumeTimer: 0,
@@ -435,6 +464,40 @@ function suspendGlowFeather(
   state.featherResumeTimer = win.setTimeout(resume, delay);
 }
 
+/** All sources discovered by one render enter in one frame, not N renders. */
+function scheduleGlowEntry(state: GlowRuntimeState, host: GlowRuntimeHost, key: string): void {
+  let batch = state.collectingEntryBatch;
+  if (!batch) {
+    const next: GlowEntryBatch = { keys: new Set(), raf: 0 };
+    state.collectingEntryBatch = next;
+    state.enterBatches.add(next);
+    next.raf = host.window().requestAnimationFrame(() => {
+      if (!state.enterBatches.delete(next)) return;
+      if (state.collectingEntryBatch === next) state.collectingEntryBatch = null;
+      for (const source of next.keys) state.enteringSources.delete(source);
+      if (next.keys.size && host.isConnected()) host.requestUpdate();
+    });
+    // Seal this synchronous render before other rAF callbacks can discover
+    // new sources: those need their own next frame, not this earlier batch.
+    queueMicrotask(() => {
+      if (state.collectingEntryBatch === next) state.collectingEntryBatch = null;
+    });
+    batch = next;
+  }
+  batch.keys.add(key);
+}
+
+function forgetGlowEntry(state: GlowRuntimeState, host: GlowRuntimeHost, key: string): void {
+  state.enteringSources.delete(key);
+  for (const batch of state.enterBatches) {
+    batch.keys.delete(key);
+    if (batch.keys.size) continue;
+    host.window().cancelAnimationFrame(batch.raf);
+    state.enterBatches.delete(batch);
+    if (state.collectingEntryBatch === batch) state.collectingEntryBatch = null;
+  }
+}
+
 export function transitionGlowSource(
   state: GlowRuntimeState,
   host: GlowRuntimeHost,
@@ -454,21 +517,12 @@ export function transitionGlowSource(
       domId = ++state.sourceSeq;
       state.renderedSources.set(key, domId);
       state.enteringSources.add(key);
-      const raf = win.requestAnimationFrame(() => {
-        if (state.enterRafs.get(key) !== raf) return;
-        state.enterRafs.delete(key);
-        state.enteringSources.delete(key);
-        if (host.isConnected()) host.requestUpdate();
-      });
-      state.enterRafs.set(key, raf);
+      scheduleGlowEntry(state, host, key);
     }
     return { domId, entering: state.enteringSources.has(key), leaving: false };
   }
   if (domId == null) return null;
-  const enterRaf = state.enterRafs.get(key);
-  if (enterRaf != null) win.cancelAnimationFrame(enterRaf);
-  state.enterRafs.delete(key);
-  state.enteringSources.delete(key);
+  forgetGlowEntry(state, host, key);
   if (!state.fadeTimers.has(key)) {
     suspendGlowFeather(state, host);
     const timer = win.setTimeout(() => {
@@ -488,12 +542,9 @@ export function forgetGlowSource(
 ): void {
   const win = host.window();
   const timer = state.fadeTimers.get(key);
-  const raf = state.enterRafs.get(key);
   if (timer != null) win.clearTimeout(timer);
-  if (raf != null) win.cancelAnimationFrame(raf);
   state.fadeTimers.delete(key);
-  state.enterRafs.delete(key);
-  state.enteringSources.delete(key);
+  forgetGlowEntry(state, host, key);
   state.renderedSources.delete(key);
   state.lastAppearance.delete(key);
 }
@@ -524,12 +575,13 @@ export function disposeGlowRuntime(
 ): void {
   const win = host.window();
   for (const timer of state.fadeTimers.values()) win.clearTimeout(timer);
-  for (const raf of state.enterRafs.values()) win.cancelAnimationFrame(raf);
+  for (const batch of state.enterBatches) win.cancelAnimationFrame(batch.raf);
   win.clearTimeout(state.featherResumeTimer);
   state.clipCache.clear();
   state.geometryWarnings.clear();
   state.fadeTimers.clear();
-  state.enterRafs.clear();
+  state.enterBatches.clear();
+  state.collectingEntryBatch = null;
   state.enteringSources.clear();
   state.renderedSources.clear();
   state.lastAppearance.clear();
diff --git a/src/houseplan-card.ts b/src/houseplan-card.ts
index 6a4bb89e..3af19a35 100755
--- a/src/houseplan-card.ts
+++ b/src/houseplan-card.ts
@@ -180,7 +180,7 @@ import {
   buildGlowClipGeometry, buildLightBarrierScene, createGlowRuntimeState,
   disposeGlowRuntime, forgetGlowSource, forgetGlowSpace, glowSourceInOpaqueBody,
   pruneGlowSources, readGlowClip, renderGlowPools, resolveGlowCandidates, resolveGlowFeather,
-  lightGeometryFingerprint, resolveLightBarrierRevision, transitionGlowSource,
+  LightBarrierPass, lightGeometryFingerprint, resolveLightBarrierRevision, transitionGlowSource,
   warnGlowGeometryFallback, writeGlowClip,
   type GlowRuntimeHost, type GlowRuntimeState, type GlowSpot,
 } from './glow-scene';
@@ -1804,6 +1804,7 @@ export class HouseplanCard extends LitElement {
   private _innerContourCache = new Map<string, number[][] | null>();
   private readonly _floorKey = floorGeometryKeyReader(this as unknown as FloorKeySource); // #744: key of the four caches above
   private readonly _glowRuntimeState: GlowRuntimeState = createGlowRuntimeState();
+  private readonly _lightBarrierPass = new LightBarrierPass();
   private readonly _glowRuntimeHost: GlowRuntimeHost = {
     window: () => this.ownerDocument.defaultView || window,
     isConnected: () => this.isConnected,
@@ -10325,6 +10326,10 @@ export class HouseplanCard extends LitElement {
     occluders: LightSegment[]; floor: number[][][]; fingerprint: string;
     masonryGeometry: any; opaqueBodies: number[][][];
   } {
+    return this._lightBarrierPass.read(space, () => this._resolveLightBarriers(space));
+  }
+
+  private _resolveLightBarriers(space: SpaceModel) {
     const raw = this._curSpaceCfg;
     const revision = resolveLightBarrierRevision({
       rawSpaceConfig: raw,
@@ -10511,8 +10516,13 @@ export class HouseplanCard extends LitElement {
   /** #780: the lazy LED chunk when the space shows a strip (ТЗ §13.1). */
   private _ledRt(space: SpaceModel) {
     // A disconnected card never applies the chunk (a late import, r1 M5).
-    return this.isConnected && ledVisible(space, this._renderDevices, this._mode === 'devices' && this._showAll, this._serverCfg?.markers)
-      ? ledRuntime(space.id, () => this.isConnected && this.requestUpdate()) : null;
+    if (!this.isConnected || !ledVisible(space, this._renderDevices, this._mode === 'devices' && this._showAll, this._serverCfg?.markers)) {
+      // The next space may have no strips, so no field render can prune the
+      // previous owner's entry frames, fade timers or cached geometry.
+      ledRelease(this);
+      return null;
+    }
+    return ledRuntime(space.id, () => this.isConnected && this.requestUpdate());
   }
 
   /** #780: the Devices-editor LED tool, its own lazy chunk (src/led-strip-card.ts). */
@@ -10617,6 +10627,10 @@ export class HouseplanCard extends LitElement {
   }
 
   protected render(): TemplateResult | typeof nothing | typeof noChange {
+    return this._lightBarrierPass.run(() => this._renderLightPass());
+  }
+
+  private _renderLightPass(): TemplateResult | typeof nothing | typeof noChange {
     try {
       const body = this._renderBody();
       // `nothing` is the only root that has no decision surface. `noChange` is
diff --git a/src/led-strip-runtime.ts b/src/led-strip-runtime.ts
index 76895886..149533b1 100755
--- a/src/led-strip-runtime.ts
+++ b/src/led-strip-runtime.ts
@@ -613,6 +613,7 @@ export interface StaticLedInput {
   owner: object;
   /** Re-render when the field chunk lands. */
   ready: () => void;
+  isConnected: () => boolean;
 }
 
 export function renderStaticLed(input: StaticLedInput): TemplateResult {
@@ -642,10 +643,11 @@ export function renderStaticLed(input: StaticLedInput): TemplateResult {
     occluders: [], floor: [], fingerprint: '',
     masonryGeometry: input.bodies.masonryGeometry, opaqueBodies: input.bodies.opaqueBodies,
   }, (LED_EPSILON_CM / input.cellCm) * input.gridPitch);
-  const module = input.scene && input.live && (fieldWanted(views) || field?.hasLedField(input.owner))
-    ? ledField(input.space.id, input.ready) : null;
+  const module = input.isConnected() && input.scene && input.live && (fieldWanted(views) || field?.hasLedField(input.owner))
+    ? ledField(input.space.id, () => input.isConnected() && input.ready()) : null;
+  if (!module) field?.releaseLedField(input.owner);
   return svg`${module ? module.renderLedField({
     views, scene: input.scene as LightBarrierScene, polygons, faces, spaceId: input.space.id, owner: input.owner,
-    requestUpdate: input.ready, isConnected: () => true,
+    requestUpdate: input.ready, isConnected: input.isConnected,
   }) : nothing}${renderLedStripes({ views, d: frame.d, faces, perUnit: input.perUnit, handlers: null })}` as unknown as TemplateResult;
 }
diff --git a/src/space-card.ts b/src/space-card.ts
index 70323a0e..f4e26204 100644
--- a/src/space-card.ts
+++ b/src/space-card.ts
@@ -18,6 +18,7 @@ import { ContentSigner } from './signing';
 import { normalizeDeviceDisplay, openingEntityReferences, referencedContentUrls } from './logic';
 import { acquireHaRegistries, activeRegistryHass, haRegistrySnapshot } from './ha-binding-status';
 import { resolvedLightSources } from './devices';
+import { ledRelease } from './led-strip-gate';
 import {
   activitySourceSignature, resolveDevicePresentation, resolvePresentationSources,
 } from './device-presentation';
@@ -297,6 +298,10 @@ class HouseplanSpaceCard extends LitElement {
     if (!config || !config.space) {
       throw new Error('houseplan-space-card: "space" is required');
     }
+    if (this._config?.space !== config.space) {
+      disposeGlowRuntime(this._glowRuntimeState, this._glowRuntimeHost);
+      ledRelease(this._glowRuntimeState);
+    }
     this._config = {
       show_button: true, button_target: '/plan-doma',
       live_states: true, show_temperature: true, show_signal: true,
@@ -309,6 +314,7 @@ class HouseplanSpaceCard extends LitElement {
     // and a blend probe alive.
     if (this._config.light_pools !== true) {
       disposeGlowRuntime(this._glowRuntimeState, this._glowRuntimeHost);
+      ledRelease(this._glowRuntimeState);
     } else if (this.isConnected) {
       this._resolveGlowBlend();
     }
@@ -369,6 +375,7 @@ class HouseplanSpaceCard extends LitElement {
     for (const runtime of this._activityRuntime.values()) window.clearTimeout(runtime.timer);
     this._activityRuntime.clear();
     disposeGlowRuntime(this._glowRuntimeState, this._glowRuntimeHost);
+    ledRelease(this._glowRuntimeState);
     this._continuityHistory = [...this._continuityHistory, ...this._continuity.trace].slice(-80);
     this._continuity.dispose();
     this._continuityDisposed = true;
diff --git a/src/space-render.ts b/src/space-render.ts
index 75649768..2ff70318 100644
--- a/src/space-render.ts
+++ b/src/space-render.ts
@@ -59,14 +59,14 @@ import {
   type Layout, type ContentItem, type SpaceCardFit,
 } from './space-geometry';
 import { resolveZeroWalls } from './zero-walls';
-import { ledAnchor, ledRuntime, ledStripsByMarker, ledVisible } from './led-strip-gate';
+import { ledAnchor, ledRelease, ledRuntime, ledStripsByMarker, ledVisible } from './led-strip-gate';
 import { geometryOpenings } from './plan-geometry-preflight';
 import { resolveDeviceAreaRelocations } from './device-area-relocation';
 import { projectDecorImage } from './decor-assets';
 import type { DecorShape } from './editors/decor/types';
 import { cachedStairRenderGeometry, stairOutline, stairStyleVars } from './stairs';
 import {
-  buildGlowClipGeometry, buildLightBarrierScene, forgetGlowSource, forgetGlowSpace,
+  buildGlowClipGeometry, buildLightBarrierScene, disposeGlowRuntime, forgetGlowSource, forgetGlowSpace,
   glowSourceInOpaqueBody, pruneGlowSources, readGlowClip, renderGlowPools,
   resolveGlowCandidates, resolveGlowFeather, lightGeometryFingerprint,
   resolveLightBarrierRevision, transitionGlowSource, warnGlowGeometryFallback, writeGlowClip,
@@ -282,7 +282,13 @@ export function buildSpaceDevices(o: StaticDeviceBuildOpts): DevItem[] {
 export function renderSpaceStatic(o: StaticRenderOpts): TemplateResult | null {
   const models = spaceModels(o.cfg);
   const space = models.find((s) => s.id === o.spaceId);
-  if (!space) return null;
+  if (!space) {
+    if (o.glowRuntime) {
+      disposeGlowRuntime(o.glowRuntime.state, o.glowRuntime.host);
+      ledRelease(o.glowRuntime.state);
+    }
+    return null;
+  }
   const disp = spaceDisplayOf(o.cfg.spaces.find((s: any) => s.id === o.spaceId));
   const colors = fillColorsOf(o.cfg.settings);
   const storedDecor = (o.cfg.settings as { decor_default_style?: Record<string, unknown> })
@@ -310,6 +316,10 @@ export function renderSpaceStatic(o: StaticRenderOpts): TemplateResult | null {
   // the same room show different Zigbee health on the two cards.
   const spaceDevs = all.filter((d) => d.space === o.spaceId);
   const devs = spaceDevs.filter((d) => !d.hidden);
+  const showLed = ledVisible(space, devs, false, o.cfg.markers);
+  const ledConnected = o.glowRuntime?.host.isConnected ?? (() => false);
+  const ledReady = () => { if (ledConnected()) o.moonHost?.requestUpdate(); };
+  if (!showLed && o.glowRuntime) ledRelease(o.glowRuntime.state);
   // #780: a marker shown as an LED strip draws no icon here and takes no slot.
   const leds = ledStripsByMarker(space);
   const iconDevs = leds.size ? devs.filter((d) => !leds.has(d.id)) : devs;
@@ -1001,13 +1011,14 @@ export function renderSpaceStatic(o: StaticRenderOpts): TemplateResult | null {
         <g class="decorlayer" pointer-events="none">${decorImages}</g>
         <g class="hp-stairs-layer" pointer-events="none">${stairShapes}</g>
         ${glowPools}
-        ${ledVisible(space, devs, false, o.cfg.markers) ? ledRuntime(space.id, () => o.moonHost?.requestUpdate())?.renderStaticLed({
+        ${showLed ? ledRuntime(space.id, ledReady)?.renderStaticLed({
           space, devices: spaceDevs, hass: planHass, virtualLights: o.virtualLights,
           defaultColor: colors.glow_light.c, paletteAlpha: colors.glow_light.a, cellCm,
           gridPitch: GRID_PITCH, iconPct, glowFor: (room) => !!o.lightPools && roomGlowOf(disp.glow, room),
           inRoom: (point, room) => pointInPolygon(point, roomPoly(room) || []), live: o.liveStates !== false,
           scene: lightScene, perUnit: pxPerUnit, owner: o.glowRuntime?.state || space,
-          ready: () => o.moonHost?.requestUpdate(),
+          ready: ledReady,
+          isConnected: ledConnected,
           bodies: { masonryGeometry: canonicalWallGeometry?.components.flatMap((c) => c.geom) || [], opaqueBodies: extras },
         }) ?? nothing : nothing}
         ${wallUnion
diff --git a/test/glow-entry-batch.test.mjs b/test/glow-entry-batch.test.mjs
new file mode 100644
index 00000000..4f6b85a7
--- /dev/null
+++ b/test/glow-entry-batch.test.mjs
@@ -0,0 +1,193 @@
+import assert from 'node:assert/strict';
+import test from 'node:test';
+import {
+  createGlowRuntimeState, disposeGlowRuntime, forgetGlowSource, forgetGlowSpace,
+  GLOW_FADE_MS, pruneGlowSources, transitionGlowSource,
+} from '../test-build/glow-scene.js';
+
+function runtime(reducedMotion = false) {
+  let seq = 0, updates = 0, connected = true;
+  const frames = new Map(), timers = new Map();
+  const win = {
+    requestAnimationFrame(cb) { const id = ++seq; frames.set(id, cb); return id; },
+    cancelAnimationFrame(id) { frames.delete(id); },
+    setTimeout(cb, delay) { const id = ++seq; timers.set(id, { cb, delay }); return id; },
+    clearTimeout(id) { timers.delete(id); },
+  };
+  const host = { window: () => win, reducedMotion: () => reducedMotion,
+    isConnected: () => connected, requestUpdate: () => { updates++; } };
+  const state = createGlowRuntimeState();
+  return { state, host, frames, timers,
+    get updates() { return updates; },
+    disconnect() { connected = false; },
+    enter(key) { return transitionGlowSource(state, host, key, true); },
+    off(key) { return transitionGlowSource(state, host, key, false); },
+    frame() { for (const [id, cb] of [...frames]) { frames.delete(id); cb(0); } },
+    dispose() { disposeGlowRuntime(state, host); },
+  };
+}
+
+for (const reduced of [false, true]) {
+  test(`50 Glow/LED entries share one frame and one update, reduced motion=${reduced}`, () => {
+    const r = runtime(reduced);
+    for (let i = 0; i < 50; i++) {
+      const result = r.enter(`floor|${i % 2 ? 'lamp' : 'led'}-${i}`);
+      assert.equal(result.entering, true);
+    }
+    assert.equal(r.frames.size, 1, 'old per-source scheduler produces 50 callbacks here');
+    assert.equal(r.updates, 0, 'entering state is painted before its next frame');
+    assert.equal(r.state.enteringSources.size, 50);
+    r.frame();
+    assert.equal(r.updates, 1);
+    assert.equal(r.state.enteringSources.size, 0);
+    assert.equal(r.frames.size, 0);
+    for (const key of r.state.renderedSources.keys()) assert.equal(r.enter(key).entering, false);
+    assert.equal(r.frames.size, 0, 'steady renders do not schedule entry again');
+    r.dispose();
+    assert.equal(r.timers.size, 0);
+  });
+}
+
+test('owners do not share their scheduler or their entering sources', () => {
+  const a = runtime(), b = runtime();
+  a.enter('floor|same'); b.enter('floor|same');
+  a.frame();
+  assert.equal(a.updates, 1); assert.equal(b.updates, 0);
+  assert.equal(b.state.enteringSources.size, 1);
+  b.frame();
+  assert.equal(b.updates, 1);
+  a.dispose(); b.dispose();
+});
+
+test('off before the entry frame preserves its peers and fade-out duration', () => {
+  const r = runtime();
+  const first = r.enter('s|a'); r.enter('s|b');
+  const off = r.off('s|a');
+  assert.deepEqual(off, { domId: first.domId, entering: false, leaving: true });
+  assert.equal(r.frames.size, 1, 'cancelling one member must not cancel another');
+  const timer = r.state.fadeTimers.get('s|a');
+  assert.equal(r.timers.get(timer).delay, GLOW_FADE_MS + 34);
+  r.frame();
+  assert.equal(r.updates, 1);
+  assert.equal(r.state.renderedSources.has('s|a'), true, 'off node survives through fade');
+  r.timers.get(timer).cb();
+  assert.equal(r.state.renderedSources.has('s|a'), false);
+  assert.equal(r.state.renderedSources.has('s|b'), true);
+  r.dispose();
+});
+
+test('rapid off/on keeps DOM identity and rejects its stale fade callback', () => {
+  const r = runtime();
+  const first = r.enter('s|a');
+  r.off('s|a');
+  const stale = r.timers.get(r.state.fadeTimers.get('s|a')).cb;
+  assert.equal(r.frames.size, 0, 'last departing entry cancels the empty batch');
+  assert.deepEqual(r.enter('s|a'), { domId: first.domId, entering: false, leaving: false });
+  stale();
+  assert.equal(r.state.renderedSources.get('s|a'), first.domId);
+  assert.equal(r.updates, 0);
+  r.dispose();
+});
+
+test('prune/space switch remove only their sources; cancelled old frame cannot consume the new batch', () => {
+  const r = runtime();
+  r.enter('old|a'); r.enter('old|b');
+  const stale = [...r.frames.values()][0];
+  pruneGlowSources(r.state, r.host, 'old', new Set(['old|b']));
+  assert.equal(r.frames.size, 1);
+  forgetGlowSpace(r.state, r.host, 'old');
+  assert.equal(r.frames.size, 0);
+  assert.equal(r.state.renderedSources.size, 0);
+  r.enter('new|c');
+  stale();
+  assert.equal(r.state.enteringSources.has('new|c'), true);
+  assert.equal(r.updates, 0);
+  r.frame();
+  assert.equal(r.updates, 1);
+  r.dispose();
+});
+
+test('disconnect/dispose prevent queued entry and fade callbacks from updating their owner', () => {
+  const r = runtime();
+  r.enter('s|a');
+  const staleFrame = [...r.frames.values()][0];
+  r.off('s|a');
+  const staleFade = r.timers.get(r.state.fadeTimers.get('s|a')).cb;
+  r.enter('s|b'); r.disconnect();
+  r.frame();
+  assert.equal(r.updates, 0);
+  r.dispose();
+  staleFrame(); staleFade();
+  assert.equal(r.updates, 0);
+  assert.equal(r.frames.size, 0); assert.equal(r.timers.size, 0);
+  assert.equal(r.state.enteringSources.size, 0);
+  assert.equal(r.state.renderedSources.size, 0);
+  assert.equal(r.state.enterBatches.size, 0);
+  assert.equal(r.state.collectingEntryBatch, null);
+});
+
+test('forget the last entry cancels its frame without affecting an already visible source', () => {
+  const r = runtime();
+  r.enter('s|visible'); r.frame();
+  r.enter('s|new');
+  forgetGlowSource(r.state, r.host, 's|new');
+  assert.equal(r.frames.size, 0);
+  assert.equal(r.state.renderedSources.has('s|visible'), true);
+  assert.equal(r.updates, 1);
+  r.dispose();
+});
+
+test('a source discovered by an earlier rAF is not consumed by an older pending batch', async () => {
+  const r = runtime();
+  r.host.window().requestAnimationFrame(() => r.enter('s|later'));
+  r.enter('s|first');
+  await Promise.resolve(); // finish the synchronous render before the browser frame
+  r.frame(); // earlier external callback, then the old entry batch
+  assert.equal(r.state.enteringSources.has('s|first'), false);
+  assert.equal(r.state.enteringSources.has('s|later'), true,
+    'the newly rendered source needs its own initial entering frame');
+  assert.equal(r.frames.size, 1);
+  assert.equal(r.updates, 1);
+  await Promise.resolve();
+  r.frame();
+  assert.equal(r.state.enteringSources.size, 0);
+  assert.equal(r.updates, 2);
+  r.dispose();
+});
+
+test('forget/re-add of the same key cannot let an earlier batch consume its new entry', async () => {
+  const r = runtime();
+  r.enter('s|a'); r.enter('s|peer');
+  await Promise.resolve();
+  forgetGlowSource(r.state, r.host, 's|a');
+  const oldFrame = [...r.frames.values()][0];
+  r.enter('s|a');
+  oldFrame();
+  assert.equal(r.state.enteringSources.has('s|a'), true);
+  assert.equal(r.state.enteringSources.has('s|peer'), false);
+  r.frame();
+  assert.equal(r.state.enteringSources.size, 0);
+  assert.equal(r.updates, 2);
+  r.dispose();
+});
+
+test('a reused runtime ignores old frames and microtasks after dispose', async () => {
+  const r = runtime();
+  r.enter('s|same');
+  const oldFrame = [...r.frames.values()][0];
+  r.dispose();
+  // Runs between the old seal-microtask and the new one. A stale seal must
+  // not clear the new collecting batch and split this peer into a second rAF.
+  queueMicrotask(() => r.enter('s|peer'));
+  r.enter('s|same');
+  oldFrame();
+  await Promise.resolve();
+  assert.equal(r.state.enteringSources.has('s|same'), true);
+  assert.equal(r.state.enteringSources.has('s|peer'), true);
+  assert.equal(r.frames.size, 1);
+  assert.equal(r.updates, 0);
+  r.frame();
+  assert.equal(r.updates, 1);
+  assert.equal(r.state.enteringSources.size, 0);
+  r.dispose();
+});
diff --git a/test/light-barrier-pass.test.mjs b/test/light-barrier-pass.test.mjs
new file mode 100644
index 00000000..71eadd4b
--- /dev/null
+++ b/test/light-barrier-pass.test.mjs
@@ -0,0 +1,64 @@
+import assert from 'node:assert/strict';
+import test from 'node:test';
+import { LightBarrierPass } from '../test-build/glow-scene.js';
+
+test('ordinary Glow and LED share one revision within a synchronous render only', () => {
+  const pass = new LightBarrierPass(), space = { id: 'floor' };
+  let builds = 0;
+  const build = () => ({ fingerprint: String(++builds) });
+  pass.run(() => {
+    const first = pass.read(space, build);
+    assert.equal(pass.read(space, build), first);
+    assert.equal(pass.read(space, build), first);
+    assert.equal(builds, 1);
+  });
+  assert.equal(pass.read(space, build).fingerprint, '2');
+  assert.equal(pass.read(space, build).fingerprint, '3');
+  pass.run(() => assert.equal(pass.read(space, build).fingerprint, '4'));
+});
+
+test('in-place plan and opening changes are fingerprinted again next render', () => {
+  const pass = new LightBarrierPass(), space = { id: 'floor', wall: 10, opening: 0 };
+  const build = () => ({ fingerprint: `${space.wall}/${space.opening}` });
+  const render = () => pass.run(() => pass.read(space, build));
+  assert.equal(render().fingerprint, '10/0');
+  space.wall = 12;
+  assert.equal(render().fingerprint, '12/0');
+  space.opening = 1;
+  assert.equal(render().fingerprint, '12/1');
+});
+
+test('owners and different space objects never share a memo, even with the same id', () => {
+  const a = new LightBarrierPass(), b = new LightBarrierPass();
+  const one = { id: 'floor' }, two = { id: 'floor' };
+  let n = 0;
+  const build = () => ({ fingerprint: String(++n) });
+  a.run(() => b.run(() => {
+    assert.equal(a.read(one, build).fingerprint, '1');
+    assert.equal(a.read(two, build).fingerprint, '2');
+    assert.equal(b.read(one, build).fingerprint, '3');
+    assert.equal(a.read(one, build).fingerprint, '1');
+  }));
+});
+
+test('throwing renders and failed builds cannot retain or poison the next read', () => {
+  const pass = new LightBarrierPass(), space = { id: 'floor' };
+  const failure = new Error('render failed');
+  assert.throws(() => pass.run(() => {
+    assert.throws(() => pass.read(space, () => { throw failure; }), failure);
+    pass.read(space, () => ({ fingerprint: 'old' }));
+    throw failure;
+  }), failure);
+  assert.equal(pass.read(space, () => ({ fingerprint: 'new' })).fingerprint, 'new');
+});
+
+test('nested synchronous passes restore the outer memo without leaking the inner one', () => {
+  const pass = new LightBarrierPass(), space = { id: 'floor' };
+  const outer = { fingerprint: 'outer' }, inner = { fingerprint: 'inner' };
+  pass.run(() => {
+    assert.equal(pass.read(space, () => outer), outer);
+    pass.run(() => assert.equal(pass.read(space, () => inner), inner));
+    assert.equal(pass.read(space, () => { throw Error('outer memo missing'); }), outer);
+  });
+  assert.equal(pass.read(space, () => inner), inner);
+});