fix(adminui): guard Alerts chip auto-clear against stale-timer race (review)

src/Server/ZB.MOM.WW.OtOpcUa.AdminUI/Components/Pages/Alerts.razor

@@ -135,6 +135,7 @@ else
     // Auto-clear timer for the per-row result chip (mirrors DriverStatusPanel): the chip is set in
     // ShowOpResult and cleared 8 s later so it doesn't persist until the next action.
     private System.Threading.Timer? _opResultClearTimer;
+    private object? _opResultClearToken;
 
     // Per-row timed-shelve duration (minutes). Keyed by AlarmId so each row's number input is
     // independent — binding every row to one shared field would couple all the inputs together.
@@ -240,13 +241,20 @@ else
         StateHasChanged();
         // Auto-clear the result chip after 8 s (mirrors DriverStatusPanel). System.Threading.Timer
         // is used (not System.Timers.Timer) so DisposeAsync can drain any in-flight callback.
+        var token = _opResultClearToken = new object();
         _opResultClearTimer?.Dispose();
         _opResultClearTimer = new System.Threading.Timer(_ =>
-        {
-            _opResultMessage = null;
-            _opResultAlarmId = "";
-            InvokeAsync(StateHasChanged);
-        }, null, TimeSpan.FromSeconds(8), Timeout.InfiniteTimeSpan);
+            InvokeAsync(() =>
+            {
+                // Ignore a stale fire: a newer action superseded this timer's chip. (Timer.Dispose does
+                // not drain an already-queued callback, so without this a stale timer could clear a
+                // freshly-set result from a different row.)
+                if (!ReferenceEquals(_opResultClearToken, token)) return;
+                _opResultMessage = null;
+                _opResultAlarmId = "";
+                StateHasChanged();
+            }),
+            null, TimeSpan.FromSeconds(8), Timeout.InfiniteTimeSpan);
     }
 
     private void OnAlarm(AlarmTransitionEvent evt) =>