diff --git a/.gitea/workflows/sop-tier-check.yml b/.gitea/workflows/sop-tier-check.yml
index 6df5fb7c..235ed633 100644
--- a/.gitea/workflows/sop-tier-check.yml
+++ b/.gitea/workflows/sop-tier-check.yml
@@ -28,15 +28,16 @@
 #
 # Environment variables:
 #   SOP_DEBUG=1          — per-API-call diagnostic lines. Default: off.
-#   SOP_LEGACY_CHECK=1   — revert to OR-gate for this run. Grace window
-#                           for PRs in-flight when AND-composition deployed.
-#                           Burn-in: remove after 2026-05-17 (7-day window).
+#   SOP_LEGACY_CHECK=1   — revert to OR-gate for this run. Intended for
+#                           emergency use only; burn-in window closed
+#                           2026-05-17 (internal#189 Phase 1).
 #
-# BURN-IN NOTE (internal#189 Phase 1): continue-on-error: true is set on
-# the tier-check job below. This prevents AND-composition from blocking
-# PRs during the 7-day burn-in. After 2026-05-17:
-#   1. Remove `continue-on-error: true` from this job block.
-#   2. Update this BURN-IN NOTE comment to mark the window closed.
+# BURN-IN CLOSED 2026-05-17 (internal#189 Phase 1): The 7-day burn-in
+# window closed. continue-on-error: true has been removed from the
+# tier-check job; AND-composition is now fully enforced. If you need
+# to temporarily re-introduce a mask, file a tracker and follow the
+# mc#774 protocol (Tier 2e lint requires a current tracker within
+# 2 lines of any continue-on-error: true).
 
 name: sop-tier-check
 
@@ -63,10 +64,6 @@ on:
 jobs:
   tier-check:
     runs-on: ubuntu-latest
-    # BURN-IN: continue-on-error prevents AND-composition from blocking
-    # PRs during the 7-day window. Remove after 2026-05-17 (mc#774).
-    # mc#774: pre-existing continue-on-error mask; root-fix and remove, do not renew silently.
-    continue-on-error: true
     permissions:
       contents: read
       pull-requests: read
diff --git a/canvas/src/components/__tests__/MemoryInspectorPanel.test.ts b/canvas/src/components/__tests__/MemoryInspectorPanel.test.ts
index 2ea69e56..797f27ac 100644
--- a/canvas/src/components/__tests__/MemoryInspectorPanel.test.ts
+++ b/canvas/src/components/__tests__/MemoryInspectorPanel.test.ts
@@ -7,7 +7,7 @@
  * itself (MemoryInspectorPanel) requires full API + store mocking and
  * is exercised by the existing MemoryTab.test.tsx.
  */
-import { describe, it, expect } from "vitest";
+import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
 import { isPluginUnavailableError, formatTTL } from "../MemoryInspectorPanel";
 
 // formatRelativeTime is not exported — tested via the component in MemoryTab.test.tsx
@@ -47,6 +47,9 @@ describe("isPluginUnavailableError", () => {
 });
 
 describe("formatTTL", () => {
+  beforeEach(() => { vi.useFakeTimers(); });
+  afterEach(() => { vi.useRealTimers(); });
+
   it("returns '' for null", () => {
     expect(formatTTL(null)).toBe("");
   });