diff --git a/extensions/diagnostics-otel/src/service.ts b/extensions/diagnostics-otel/src/service.ts
index 8c3f607fd66..3ada2aefacc 100644
--- a/extensions/diagnostics-otel/src/service.ts
+++ b/extensions/diagnostics-otel/src/service.ts
@@ -2222,6 +2222,8 @@ export function createDiagnosticsOtelService(): OpenClawPluginService {
             case "diagnostic.liveness.warning":
               recordLivenessWarning(evt);
               return;
+            case "diagnostic.phase.completed":
+              return;
             case "run.started":
               recordRunStarted(evt, metadata);
               return;
diff --git a/src/logging/diagnostic-phase.ts b/src/logging/diagnostic-phase.ts
index abd8b379a40..d6b8ddbb1bc 100644
--- a/src/logging/diagnostic-phase.ts
+++ b/src/logging/diagnostic-phase.ts
@@ -39,7 +39,7 @@ export function getCurrentDiagnosticPhase(): string | undefined {
 }
 
 export function getRecentDiagnosticPhases(limit = 8): DiagnosticPhaseSnapshot[] {
-  return recentPhases.slice(-Math.max(0, limit)).map((phase) => ({ ...phase }));
+  return recentPhases.slice(-Math.max(0, limit)).map((phase) => Object.assign({}, phase));
 }
 
 export function recordDiagnosticPhase(snapshot: DiagnosticPhaseSnapshot): void {
diff --git a/src/logging/diagnostic.test.ts b/src/logging/diagnostic.test.ts
index ac93e0e2212..26eae67d146 100644
--- a/src/logging/diagnostic.test.ts
+++ b/src/logging/diagnostic.test.ts
@@ -397,7 +397,7 @@ describe("stuck session diagnostics threshold", () => {
     }
 
     expect(warnSpy).toHaveBeenCalledWith(expect.stringContaining("terminalProgressStale=true"));
-    expect(events.filter((event) => event.type === "session.stalled").at(-1)).toMatchObject({
+    expect(events.findLast((event) => event.type === "session.stalled")).toMatchObject({
       terminalProgressStale: true,
       lastProgressReason: "codex_app_server:notification:rawResponseItem/completed",
     });
@@ -754,9 +754,7 @@ describe("stuck session diagnostics threshold", () => {
 
     expect(warnSpy).toHaveBeenCalledWith(expect.stringContaining("phase=startup.plugins.load"));
     expect(warnSpy).toHaveBeenCalledWith(expect.stringContaining("work=[queued=main("));
-    expect(
-      events.filter((event) => event.type === "diagnostic.liveness.warning").at(-1),
-    ).toMatchObject({
+    expect(events.findLast((event) => event.type === "diagnostic.liveness.warning")).toMatchObject({
       phase: "startup.plugins.load",
       queuedWorkLabels: [expect.stringContaining("main(")],
     });