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 9bdb9c59..15175be0 100644
--- a/tests/Server/ZB.MOM.WW.OtOpcUa.Host.IntegrationTests/TwoNodeClusterHarness.cs
+++ b/tests/Server/ZB.MOM.WW.OtOpcUa.Host.IntegrationTests/TwoNodeClusterHarness.cs
@@ -456,6 +456,41 @@ public sealed class TwoNodeClusterHarness : IAsyncDisposable
             $"B up={Akka.Cluster.Cluster.Get(b).State.Members.Count(m => m.Status == MemberStatus.Up)}");
     }
 
+    /// <summary>
+    ///     Stops a node's hosted services, then disposes it.
+    /// </summary>
+    /// <remarks>
+    ///     <para>
+    ///         <b><see cref="IHost.StopAsync"/> is not optional, and disposal is not a substitute for
+    ///         it.</b> <c>Host.DisposeAsync</c> only disposes the service provider; it never invokes
+    ///         <see cref="IHostedService.StopAsync"/>. Akka.Hosting terminates the
+    ///         <see cref="ActorSystem"/> from that callback, so a disposed-but-never-stopped node
+    ///         leaves a live ActorSystem — remoting transport, dispatcher thread pools and all —
+    ///         rooted for the lifetime of the test process.
+    ///     </para>
+    ///     <para>
+    ///         Every test here starts two of them, so the cost compounded across the suite: a single
+    ///         test host was measured at <b>~30 GB RSS</b>, which starved timeout-based assertions
+    ///         into false failures that looked exactly like real regressions.
+    ///     </para>
+    /// </remarks>
+    /// <param name="node">The node to stop and dispose.</param>
+    private static async Task ShutDownAsync(WebApplication node)
+    {
+        // Best-effort: a node already stopped (or mid-CoordinatedShutdown from a failover test)
+        // throws here, and a failure to stop must never mask the test's own assertion failure.
+        try
+        {
+            await node.StopAsync(TimeSpan.FromSeconds(10));
+        }
+        catch
+        {
+            // fall through to disposal
+        }
+
+        await node.DisposeAsync();
+    }
+
     private static int AllocateFreePort()
     {
         using var listener = new TcpListener(System.Net.IPAddress.Parse(LoopbackHost), 0);
@@ -468,8 +503,8 @@ public sealed class TwoNodeClusterHarness : IAsyncDisposable
     /// <summary>Asynchronously disposes both nodes and cleans up the SQL database if used.</summary>
     public async ValueTask DisposeAsync()
     {
-        if (NodeB is not null) await NodeB.DisposeAsync();
-        if (NodeA is not null) await NodeA.DisposeAsync();
+        if (NodeB is not null) await ShutDownAsync(NodeB);
+        if (NodeA is not null) await ShutDownAsync(NodeA);
         if (_sqlConnString is not null)
         {
             try { await DropSqlDatabaseAsync(_sqlConnString); }
diff --git a/tests/Server/ZB.MOM.WW.OtOpcUa.Host.IntegrationTests/ZB.MOM.WW.OtOpcUa.Host.IntegrationTests.csproj b/tests/Server/ZB.MOM.WW.OtOpcUa.Host.IntegrationTests/ZB.MOM.WW.OtOpcUa.Host.IntegrationTests.csproj
index c678f2e0..9ae4ff79 100644
--- a/tests/Server/ZB.MOM.WW.OtOpcUa.Host.IntegrationTests/ZB.MOM.WW.OtOpcUa.Host.IntegrationTests.csproj
+++ b/tests/Server/ZB.MOM.WW.OtOpcUa.Host.IntegrationTests/ZB.MOM.WW.OtOpcUa.Host.IntegrationTests.csproj
@@ -30,4 +30,17 @@
         <ProjectReference Include="..\..\..\src\Server\ZB.MOM.WW.OtOpcUa.Security\ZB.MOM.WW.OtOpcUa.Security.csproj" />
     </ItemGroup>
 
+    <PropertyGroup>
+        <!--
+            Workstation GC. Referencing the Host drags in the ASP.NET Core framework reference, which
+            turns Server GC ON by default — one heap per core, tuned for throughput and deliberately
+            reluctant to return memory to the OS. That is right for a server and wrong for a test
+            host: across ~200 tests this process was measured at ~30 GB RSS, which starved
+            timeout-based assertions into false failures indistinguishable from real regressions.
+            Nothing here needs Server GC's throughput.
+        -->
+        <ServerGarbageCollection>false</ServerGarbageCollection>
+        <ConcurrentGarbageCollection>false</ConcurrentGarbageCollection>
+    </PropertyGroup>
+
 </Project>