diff --git a/tests/Server/ZB.MOM.WW.OtOpcUa.Host.IntegrationTests/TwoNodeClusterHarness.cs b/tests/Server/ZB.MOM.WW.OtOpcUa.Host.IntegrationTests/TwoNodeClusterHarness.cs
index 15175be0..cd18796f 100644
--- a/tests/Server/ZB.MOM.WW.OtOpcUa.Host.IntegrationTests/TwoNodeClusterHarness.cs
+++ b/tests/Server/ZB.MOM.WW.OtOpcUa.Host.IntegrationTests/TwoNodeClusterHarness.cs
@@ -204,15 +204,22 @@ public sealed class TwoNodeClusterHarness : IAsyncDisposable
     }
 
     /// <summary>
-    /// Gracefully shuts down node B via <see cref="WebApplication.DisposeAsync"/>, which runs
-    /// CoordinatedShutdown → Cluster.Leave. Node A sees the member transition to Removed within
-    /// a couple of seconds. Use this for failover scenarios; call <see cref="RestartNodeBAsync"/>
-    /// to bring it back on the same Akka port.
+    /// Gracefully shuts node B down, so CoordinatedShutdown runs and the node performs a
+    /// Cluster.Leave; node A sees the member transition to Removed within a couple of seconds.
+    /// Use this for failover scenarios; call <see cref="RestartNodeBAsync"/> to bring it back on
+    /// the same Akka port.
     /// </summary>
+    /// <remarks>
+    ///     This used to call <c>DisposeAsync</c> alone, on the stated belief that disposal "runs
+    ///     CoordinatedShutdown". It does not — see <see cref="ShutDownAsync"/>. A disposed-but-never-
+    ///     stopped node never leaves the cluster gracefully; node A only notices once the failure
+    ///     detector times it out, which is a slower and materially different path from the graceful
+    ///     leave these failover tests mean to exercise.
+    /// </remarks>
     public async Task StopNodeBAsync()
     {
         if (NodeB is null) return;
-        await NodeB.DisposeAsync();
+        await ShutDownAsync(NodeB);
         NodeB = null!;
     }