diff --git a/test/Grpc.IntegrationTests/TracingIntegrationTests.cs b/test/Grpc.IntegrationTests/TracingIntegrationTests.cs
index 6bd5c421..041c76de 100644
--- a/test/Grpc.IntegrationTests/TracingIntegrationTests.cs
+++ b/test/Grpc.IntegrationTests/TracingIntegrationTests.cs
@@ -1,6 +1,8 @@
 // Copyright (c) Microsoft Corporation.
 // Licensed under the MIT License.
 
+using System.Collections;
+using System.Collections.Concurrent;
 using System.Diagnostics;
 using FluentAssertions;
 using Microsoft.DurableTask.Client;
@@ -16,7 +18,7 @@ public TracingIntegrationTests(ITestOutputHelper output, GrpcSidecarFixture side
     {
     }
 
-    static ActivityListener CreateListener(string[] sources, ICollection<Activity> activities)
+    static ActivityListener CreateListener(string[] sources, ConcurrentBag<Activity> activities)
     {
         ActivityListener listener = new();
 
@@ -39,7 +41,7 @@ static ActivityListener CreateListener(string[] sources, ICollection<Activity> a
     [Fact]
     public async Task MultiTaskOrchestration()
     {
-        var activities = new List<Activity>();
+        var activities = new ConcurrentBag<Activity>();
 
         using var listener = CreateListener(ActivitySourceNames, activities);
 
@@ -70,6 +72,9 @@ public async Task MultiTaskOrchestration()
             OrchestrationMetadata metadata = await server.Client.WaitForInstanceCompletionAsync(instanceId, getInputsAndOutputs: true, this.TimeoutToken);
         }
 
+        await server.DisposeAsync();
+        listener.Dispose();
+
         var testActivity = activities.Single(a => a.Source == TestActivitySource && a.OperationName == "Test");
         var createActivity = activities.Single(a => a.Source.Name == CoreActivitySourceName && a.OperationName == $"create_orchestration:{orchestratorName}");
 
@@ -148,7 +153,7 @@ public async Task MultiTaskOrchestration()
     [Fact]
     public async Task TaskOrchestrationWithActivityFailure()
     {
-        var activities = new List<Activity>();
+        var activities = new ConcurrentBag<Activity>();
 
         using var listener = CreateListener(ActivitySourceNames, activities);
 
@@ -178,6 +183,9 @@ public async Task TaskOrchestrationWithActivityFailure()
             OrchestrationMetadata metadata = await server.Client.WaitForInstanceCompletionAsync(instanceId, getInputsAndOutputs: true, this.TimeoutToken);
         }
 
+        await server.DisposeAsync();
+        listener.Dispose();
+
         var testActivity = activities.Single(a => a.Source == TestActivitySource && a.OperationName == "Test");
         var createActivity = activities.Single(a => a.Source.Name == CoreActivitySourceName && a.OperationName == $"create_orchestration:{orchestratorName}");
 
@@ -248,7 +256,7 @@ public async Task TaskOrchestrationWithActivityFailure()
     [Fact]
     public async Task TaskWithSuborchestration()
     {
-        var activities = new List<Activity>();
+        var activities = new ConcurrentBag<Activity>();
 
         using var listener = CreateListener(ActivitySourceNames, activities);
         
@@ -287,6 +295,9 @@ public async Task TaskWithSuborchestration()
             OrchestrationMetadata metadata = await server.Client.WaitForInstanceCompletionAsync(instanceId, getInputsAndOutputs: true, this.TimeoutToken);
         }
 
+        await server.DisposeAsync();
+        listener.Dispose();
+
         var testActivity = activities.Single(a => a.Source == TestActivitySource && a.OperationName == "Test");
         var createActivity = activities.Single(a => a.Source.Name == CoreActivitySourceName && a.OperationName == $"create_orchestration:{orchestratorName}");
 
@@ -356,7 +367,7 @@ public async Task TaskWithSuborchestration()
     [Fact]
     public async Task TaskWithSuborchestrationFailure()
     {
-        var activities = new List<Activity>();
+        var activities = new ConcurrentBag<Activity>();
 
         using var listener = CreateListener(ActivitySourceNames, activities);
         
@@ -395,6 +406,9 @@ public async Task TaskWithSuborchestrationFailure()
             OrchestrationMetadata metadata = await server.Client.WaitForInstanceCompletionAsync(instanceId, getInputsAndOutputs: true, this.TimeoutToken);
         }
 
+        await server.DisposeAsync();
+        listener.Dispose();
+
         var testActivity = activities.Single(a => a.Source == TestActivitySource && a.OperationName == "Test");
         var createActivity = activities.Single(a => a.Source.Name == CoreActivitySourceName && a.OperationName == $"create_orchestration:{orchestratorName}");
 
@@ -467,7 +481,7 @@ public async Task TaskWithSuborchestrationFailure()
     [Fact]
     public async Task TaskOrchestrationWithSentEvent()
     {
-        var activities = new List<Activity>();
+        var activities = new ConcurrentBag<Activity>();
 
         using var listener = CreateListener(ActivitySourceNames, activities);
 
@@ -499,6 +513,9 @@ public async Task TaskOrchestrationWithSentEvent()
             OrchestrationMetadata metadata = await server.Client.WaitForInstanceCompletionAsync(instanceId, getInputsAndOutputs: true, this.TimeoutToken);
         }
 
+        await server.DisposeAsync();
+        listener.Dispose();
+
         var testActivity = activities.Single(a => a.Source == TestActivitySource && a.OperationName == "Test");
         var createActivity = activities.Single(a => a.Source.Name == CoreActivitySourceName && a.OperationName == $"create_orchestration:{orchestratorName}");
 
@@ -547,7 +564,7 @@ public async Task TaskOrchestrationWithSentEvent()
     [Fact]
     public async Task TaskOrchestrationWithTimer()
     {
-        var activities = new List<Activity>();
+        var activities = new ConcurrentBag<Activity>();
 
         using var listener = CreateListener(ActivitySourceNames, activities);
 
@@ -581,6 +598,9 @@ public async Task TaskOrchestrationWithTimer()
             OrchestrationMetadata metadata = await server.Client.WaitForInstanceCompletionAsync(instanceId, getInputsAndOutputs: true, this.TimeoutToken);
         }
 
+        await server.DisposeAsync();
+        listener.Dispose();
+
         fireAt.Should().NotBe(default);
 
         var testActivity = activities.Single(a => a.Source == TestActivitySource && a.OperationName == "Test");
@@ -632,7 +652,7 @@ public async Task TaskOrchestrationWithTimer()
     [Fact]
     public async Task ClientRaiseEvent()
     {
-        var activities = new List<Activity>();
+        var activities = new ConcurrentBag<Activity>();
 
         using var listener = CreateListener(ActivitySourceNames, activities);
 
@@ -664,6 +684,9 @@ await server.Client.WaitForInstanceCompletionAsync(instanceId, getInputsAndOutpu
                     this.TimeoutToken);
         }
 
+        await server.DisposeAsync();
+        listener.Dispose();
+
         var testActivity = activities.Single(a => a.Source == TestActivitySource && a.OperationName == "Test");
 
         var raiseEventActivity = activities.Single(a =>