diff --git a/.github/workflows/validate.yml b/.github/workflows/validate.yml
index 8233e105..a629a0f7 100644
--- a/.github/workflows/validate.yml
+++ b/.github/workflows/validate.yml
@@ -1141,7 +1141,8 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v7
-        with: { ref: ${{ github.sha }} }
+        with:
+          ref: ${{ github.sha }}
       - uses: actions/setup-node@v7
         with: { node-version: 22 }
       - name: Зафиксировать tree кандидата
diff --git a/test/validate-workflow.test.mjs b/test/validate-workflow.test.mjs
index 7e5bcaa0..1a5d4e03 100644
--- a/test/validate-workflow.test.mjs
+++ b/test/validate-workflow.test.mjs
@@ -456,6 +456,8 @@ test('журнал свидетелей changed_mutants: rerun продолжа
 
 test('#541: Validate всегда публикует proof точной попытки, а reuse раскрывает источник', () => {
   const workflow = read('validate.yml');
+  assert.doesNotMatch(workflow, /with:\s*\{[^\n]*\$\{\{/,
+    'GitHub does not parse an unquoted expression inside a YAML flow mapping');
   const proofAt = workflow.indexOf('\n  proof:\n');
   assert.ok(proofAt > 0, 'финальная proof job существует');
   const proof = workflow.slice(proofAt);