diff --git a/demo/smoke_post_write_adoption.mjs b/demo/smoke_post_write_adoption.mjs
index 1cd3f8a9..a322964f 100644
--- a/demo/smoke_post_write_adoption.mjs
+++ b/demo/smoke_post_write_adoption.mjs
@@ -80,6 +80,13 @@ const out = await page.evaluate(async () => {
   };
 
   const reset = async (scenario) => {
+    // Ревью r2 M1: отложенная запись предыдущего сценария иначе доживает до
+    // следующего и флашится безусловным `if (pending) flush()` внутри
+    // `_deleteSpace`; мок отвечает `{}` без `rev`, запасной путь «rev + 1»
+    // двигает ревизию по ЧУЖОМУ телу, и отказная ветка выглядит принявшей.
+    // Сценарии обязаны быть независимы — так же чистится smoke_danger_confirmation.
+    card._saveConfigDebounced.cancel();
+    card._persistLayout.cancel();
     server = { config: freshConfig(), layout: {}, cfgRev: 10, layRev: 20 };
     concurrentHref = `media-source://image/${scenario}-500`;
     adoption.restoreCached({ config: structuredClone(server.config), rev: 10, layout: {}, layout_rev: 20 });
diff --git a/scripts/mutation-gate.mjs b/scripts/mutation-gate.mjs
index 52baf458..7406b4f4 100644
--- a/scripts/mutation-gate.mjs
+++ b/scripts/mutation-gate.mjs
@@ -8555,6 +8555,20 @@ const MUTANT_DEFINITIONS = [
         + '        || contentFingerprint(current) !== attempt.attemptedFingerprint) return false;',
     }],
   },
+  {
+    id: 'post-write-tail-runs-on-refused-gate',
+    guard: 'node demo/smoke_post_write_adoption.mjs',
+    because: '#500 r1 M1: a post-write caller whose adoption was refused must skip its tail — '
+      + 'clearing history, bumping the geometry epoch and toasting «отменено» on a body the card '
+      + 'never adopted leaves the frontend describing state the server does not have; the scheduled '
+      + 'reload owns the tail. Guarded by the smoke, so the review gate runs it (r2 M1: the witness '
+      + 'was red for a round and nobody saw it — CI never ran this smoke)',
+    patches: [{
+      file: 'src/houseplan-editor-runtime.ts',
+      find: "      if (adopted.status !== 'adopted') return; // asset wait: the scheduled reload owns the tail",
+      replace: '      void adopted; // mutant: the tail runs on a body that was never adopted',
+    }],
+  },
   {
     id: 'post-write-skips-asset-gate',
     guard: 'node --test test/config-adoption.test.mjs',