diff --git a/web/hwlab-cloud-web/src/stores/workbench.ts b/web/hwlab-cloud-web/src/stores/workbench.ts
index b979e6de..3ba54e31 100644
--- a/web/hwlab-cloud-web/src/stores/workbench.ts
+++ b/web/hwlab-cloud-web/src/stores/workbench.ts
@@ -1428,7 +1428,7 @@ function nonBlockingProjection(projection: ProjectionDiagnostic | null): Project
       const base = { ...message, traceId: canonicalTraceId, runnerTrace, updatedAt: new Date().toISOString() };
       if (message.role === "user" && userMessageId) return { ...base, id: userMessageId, messageId: userMessageId, turnId };
       if (message.role === "agent") {
-        const next = { ...base, ...admissionTiming };
+        const next = { ...base, ...stableAdmissionTimingPatchForRunningMessage(message, admissionTiming) };
         return {
           ...next,
           ...(assistantMessageId ? { id: assistantMessageId, messageId: assistantMessageId } : {}),
@@ -1440,6 +1440,21 @@ function nonBlockingProjection(projection: ProjectionDiagnostic | null): Project
     return canonicalTraceId;
   }
 
+  function stableAdmissionTimingPatchForRunningMessage(message: ChatMessage, patch: Partial<ChatMessage>): Partial<ChatMessage> {
+    const incoming = patch.timing;
+    const existing = message.timing;
+    if (!incoming || !existing?.startedAt || !isRunningMessage(message)) return patch;
+    const timing = {
+      ...incoming,
+      startedAt: existing.startedAt,
+      lastEventAt: existing.lastEventAt ?? incoming.lastEventAt ?? existing.startedAt,
+      finishedAt: null,
+      durationMs: null,
+      valuesRedacted: incoming.valuesRedacted !== false,
+    } as WorkbenchTurnTimingProjection;
+    return { ...patch, timing, startedAt: timing.startedAt ?? null, lastEventAt: timing.lastEventAt ?? null, finishedAt: null, durationMs: null };
+  }
+
   function optimisticAdmissionTimingPatch(lifecycle: AgentChatResponse): Partial<ChatMessage> {
     const patch = messageTimingPatch(lifecycle);
     if (patch.timing?.startedAt && patch.timing?.lastEventAt) return patch;