diff --git a/web/hwlab-cloud-web/src/stores/workbench.ts b/web/hwlab-cloud-web/src/stores/workbench.ts
index 9ba3d642..b979e6de 100644
--- a/web/hwlab-cloud-web/src/stores/workbench.ts
+++ b/web/hwlab-cloud-web/src/stores/workbench.ts
@@ -1810,36 +1810,13 @@ function messageTimingPatch(value: unknown): Partial<ChatMessage> {
 }
 
 function messageTimingPatchForMerge(message: ChatMessage, value: unknown): Partial<ChatMessage> {
-  const patch = messageTimingPatch(value);
-  if (!patch.timing) return patch;
-  const terminal = timingPatchIsTerminal(value, patch.timing);
-  const durationMs = terminal
-    ? terminalTimingDurationMsForMerge(message, patch.timing)
-    : maxFiniteNumber(patch.timing.durationMs, message.durationMs, message.timing?.durationMs, message.runnerTrace?.durationMs, message.runnerTrace?.timing?.durationMs);
-  const timing = { ...patch.timing, durationMs } as WorkbenchTurnTimingProjection;
-  return { timing, startedAt: timing.startedAt ?? null, lastEventAt: timing.lastEventAt ?? null, finishedAt: timing.finishedAt ?? null, durationMs };
-}
-
-function terminalTimingDurationMsForMerge(message: ChatMessage, timing: WorkbenchTurnTimingProjection): number | null {
-  const elapsed = elapsedTimingDurationMs(timing);
-  const maximum = maxFiniteNumber(timing.durationMs, elapsed, message.durationMs, message.timing?.durationMs, message.runnerTrace?.durationMs, message.runnerTrace?.timing?.durationMs);
-  if (maximum !== null) return maximum;
-  return firstFiniteNumber(timing.durationMs, elapsed, message.durationMs, message.timing?.durationMs, message.runnerTrace?.durationMs, message.runnerTrace?.timing?.durationMs);
-}
-
-function timingPatchIsTerminal(value: unknown, timing: WorkbenchTurnTimingProjection): boolean {
-  const record = recordValue(value);
-  const trace = recordValue(record?.runnerTrace);
-  const status = normalizedStatusText(record?.status ?? record?.traceStatus ?? trace?.status ?? trace?.traceStatus);
-  return Boolean(timing.finishedAt || isTerminalMessageStatus(status));
-}
-
-function elapsedTimingDurationMs(timing: WorkbenchTurnTimingProjection): number | null {
-  const start = timing.startedAt ? Date.parse(timing.startedAt) : NaN;
-  const endedAt = timing.finishedAt ?? timing.lastEventAt;
-  const end = endedAt ? Date.parse(endedAt) : NaN;
-  if (!Number.isFinite(start) || !Number.isFinite(end) || end < start) return null;
-  return Math.trunc(end - start);
+  void value;
+  // Trace/result hydration may update runnerTrace and TraceTimeline, but the
+  // main Code Agent card timing is a durable message projection field. Do not
+  // let trace snapshots or terminal result polling rewrite message.timing;
+  // otherwise visible card elapsed can jump or diverge from the sealed message
+  // projection when trace rows arrive out of order.
+  return messageTimingPatch(message);
 }
 
 function firstPositiveFiniteNumber(...values: unknown[]): number | null {