diff --git a/tests/ZB.MOM.WW.ScadaBridge.CentralUI.PlaywrightTests/Cluster/CliRunner.cs b/tests/ZB.MOM.WW.ScadaBridge.CentralUI.PlaywrightTests/Cluster/CliRunner.cs
index 1c40b2e9..16d3b72d 100644
--- a/tests/ZB.MOM.WW.ScadaBridge.CentralUI.PlaywrightTests/Cluster/CliRunner.cs
+++ b/tests/ZB.MOM.WW.ScadaBridge.CentralUI.PlaywrightTests/Cluster/CliRunner.cs
@@ -41,7 +41,7 @@ public static class CliRunner
     private const string CliPassword = "password";
 
     private static readonly object DllLock = new();
-    private static string? _cliDll;
+    private static volatile string? _cliDll;
 
     /// <summary>
     /// Management URL the CLI connects to (via the Traefik load balancer).
@@ -111,6 +111,9 @@ public static class CliRunner
         catch (OperationCanceledException)
         {
             TryKill(process);
+            // Drain both pipes so the abandoned read tasks complete cleanly before disposal.
+            try { await Task.WhenAll(stdoutTask, stderrTask).WaitAsync(TimeSpan.FromSeconds(5)); }
+            catch { /* best-effort — we are already throwing TimeoutException */ }
             throw new TimeoutException(
                 $"CLI [{string.Join(' ', args)}] did not exit within {Timeout.TotalSeconds:F0}s and was killed.");
         }
diff --git a/tests/ZB.MOM.WW.ScadaBridge.CentralUI.PlaywrightTests/Cluster/ClusterAvailability.cs b/tests/ZB.MOM.WW.ScadaBridge.CentralUI.PlaywrightTests/Cluster/ClusterAvailability.cs
index 1ebedd81..acf02473 100644
--- a/tests/ZB.MOM.WW.ScadaBridge.CentralUI.PlaywrightTests/Cluster/ClusterAvailability.cs
+++ b/tests/ZB.MOM.WW.ScadaBridge.CentralUI.PlaywrightTests/Cluster/ClusterAvailability.cs
@@ -32,7 +32,7 @@ public static class ClusterAvailability
         {
             if (!cached)
             {
-                SkippedCount++;
+                System.Threading.Interlocked.Increment(ref SkippedCount);
             }
 
             return cached;
@@ -46,7 +46,7 @@ public static class ClusterAvailability
         catch
         {
             _cached = false;
-            SkippedCount++;
+            System.Threading.Interlocked.Increment(ref SkippedCount);
         }
 
         return _cached.Value;