diff --git a/build/common.props b/build/common.props
index b35fbea512..919c99c4ac 100644
--- a/build/common.props
+++ b/build/common.props
@@ -5,7 +5,7 @@
     <LangVersion>latest</LangVersion>
     <MajorVersion>4</MajorVersion>
     <MinorVersion>28</MinorVersion>
-    <PatchVersion>2</PatchVersion>
+    <PatchVersion>3</PatchVersion>
     <BuildNumber Condition="'$(BuildNumber)' == '' ">0</BuildNumber>
     <PreviewVersion></PreviewVersion>
     
diff --git a/src/WebJobs.Script/Diagnostics/FileLogger.cs b/src/WebJobs.Script/Diagnostics/FileLogger.cs
index 12a42acc53..b74fee74a6 100644
--- a/src/WebJobs.Script/Diagnostics/FileLogger.cs
+++ b/src/WebJobs.Script/Diagnostics/FileLogger.cs
@@ -93,7 +93,7 @@ public void Log<TState>(LogLevel logLevel, EventId eventId, TState state, Except
             {
                 _fileWriter.AppendLine(formattedMessage);
             }
-            catch (Exception ex) when (!ex.IsFatal())
+            catch (Exception)
             {
                 // Make sure the Logger doesn't throw if there are Exceptions (disk full, etc).
             }
diff --git a/src/WebJobs.Script/Workers/Rpc/FunctionRegistration/RpcFunctionInvocationDispatcher.cs b/src/WebJobs.Script/Workers/Rpc/FunctionRegistration/RpcFunctionInvocationDispatcher.cs
index b4c820ecd7..e8de96d00c 100644
--- a/src/WebJobs.Script/Workers/Rpc/FunctionRegistration/RpcFunctionInvocationDispatcher.cs
+++ b/src/WebJobs.Script/Workers/Rpc/FunctionRegistration/RpcFunctionInvocationDispatcher.cs
@@ -187,7 +187,7 @@ internal async void ShutdownWebhostLanguageWorkerChannels()
             await _webHostLanguageWorkerChannelManager?.ShutdownChannelsAsync();
         }
 
-        private void SetDispatcherStateToInitialized(Dictionary<string, TaskCompletionSource<IRpcWorkerChannel>> webhostLanguageWorkerChannel = null)
+        private void SetDispatcherStateToInitialized(IDictionary<string, TaskCompletionSource<IRpcWorkerChannel>> webhostLanguageWorkerChannel = null)
         {
             // RanToCompletion indicates successful process startup
             if (State != FunctionInvocationDispatcherState.Initialized
@@ -198,7 +198,7 @@ private void SetDispatcherStateToInitialized(Dictionary<string, TaskCompletionSo
             }
         }
 
-        private void StartWorkerProcesses(int startIndex, Func<IEnumerable<string>, Task> startAction, bool initializeDispatcher = false, Dictionary<string, TaskCompletionSource<IRpcWorkerChannel>> webhostLanguageWorkerChannel = null, IEnumerable<string> functionLanguages = null)
+        private void StartWorkerProcesses(int startIndex, Func<IEnumerable<string>, Task> startAction, bool initializeDispatcher = false, IDictionary<string, TaskCompletionSource<IRpcWorkerChannel>> webhostLanguageWorkerChannel = null, IEnumerable<string> functionLanguages = null)
         {
             Task.Run(async () =>
             {
@@ -309,7 +309,7 @@ public async Task InitializeAsync(IEnumerable<FunctionMetadata> functions, Cance
             if (Utility.IsSupportedRuntime(_workerRuntime, _workerConfigs) || _environment.IsMultiLanguageRuntimeEnvironment())
             {
                 State = FunctionInvocationDispatcherState.Initializing;
-                Dictionary<string, TaskCompletionSource<IRpcWorkerChannel>> webhostLanguageWorkerChannels = _webHostLanguageWorkerChannelManager.GetChannels(_workerRuntime);
+                IDictionary<string, TaskCompletionSource<IRpcWorkerChannel>> webhostLanguageWorkerChannels = _webHostLanguageWorkerChannelManager.GetChannels(_workerRuntime);
                 if (webhostLanguageWorkerChannels != null)
                 {
                     int workerProcessCount = 0;
diff --git a/src/WebJobs.Script/Workers/Rpc/IWebHostRpcWorkerChannelManager.cs b/src/WebJobs.Script/Workers/Rpc/IWebHostRpcWorkerChannelManager.cs
index e8969ef218..9df04d3d62 100644
--- a/src/WebJobs.Script/Workers/Rpc/IWebHostRpcWorkerChannelManager.cs
+++ b/src/WebJobs.Script/Workers/Rpc/IWebHostRpcWorkerChannelManager.cs
@@ -11,7 +11,7 @@ public interface IWebHostRpcWorkerChannelManager
     {
         Task<IRpcWorkerChannel> InitializeChannelAsync(IEnumerable<RpcWorkerConfig> workerConfigs, string language);
 
-        Dictionary<string, TaskCompletionSource<IRpcWorkerChannel>> GetChannels(string language);
+        IDictionary<string, TaskCompletionSource<IRpcWorkerChannel>> GetChannels(string language);
 
         Task SpecializeAsync();
 
diff --git a/src/WebJobs.Script/Workers/Rpc/WebHostRpcWorkerChannelManager.cs b/src/WebJobs.Script/Workers/Rpc/WebHostRpcWorkerChannelManager.cs
index ef2dae92f5..34ba5b8dc1 100644
--- a/src/WebJobs.Script/Workers/Rpc/WebHostRpcWorkerChannelManager.cs
+++ b/src/WebJobs.Script/Workers/Rpc/WebHostRpcWorkerChannelManager.cs
@@ -7,9 +7,7 @@
 using System.Linq;
 using System.Reactive.Linq;
 using System.Threading.Tasks;
-using Microsoft.Azure.AppService.Proxy.Common.Extensions;
 using Microsoft.Azure.AppService.Proxy.Common.Infra;
-using Microsoft.Azure.AppService.Proxy.Runtime;
 using Microsoft.Azure.WebJobs.Script.Config;
 using Microsoft.Azure.WebJobs.Script.Diagnostics;
 using Microsoft.Azure.WebJobs.Script.Eventing;
@@ -36,7 +34,7 @@ public class WebHostRpcWorkerChannelManager : IWebHostRpcWorkerChannelManager
         private Action _shutdownStandbyWorkerChannels;
         private IConfiguration _config;
 
-        private ConcurrentDictionary<string, Dictionary<string, TaskCompletionSource<IRpcWorkerChannel>>> _workerChannels = new ConcurrentDictionary<string, Dictionary<string, TaskCompletionSource<IRpcWorkerChannel>>>(StringComparer.OrdinalIgnoreCase);
+        private ConcurrentDictionary<string, ConcurrentDictionary<string, TaskCompletionSource<IRpcWorkerChannel>>> _workerChannels = new(StringComparer.OrdinalIgnoreCase);
 
         public WebHostRpcWorkerChannelManager(IScriptEventManager eventManager,
                                               IEnvironment environment,
@@ -101,7 +99,7 @@ await rpcWorkerChannel.StartWorkerProcessAsync().ContinueWith(processStartTask =
 
         internal Task<IRpcWorkerChannel> GetChannelAsync(string language)
         {
-            if (!string.IsNullOrEmpty(language) && _workerChannels.TryGetValue(language, out Dictionary<string, TaskCompletionSource<IRpcWorkerChannel>> workerChannels))
+            if (!string.IsNullOrEmpty(language) && _workerChannels.TryGetValue(language, out ConcurrentDictionary<string, TaskCompletionSource<IRpcWorkerChannel>> workerChannels))
             {
                 if (workerChannels.Count > 0 && workerChannels.TryGetValue(workerChannels.Keys.First(), out TaskCompletionSource<IRpcWorkerChannel> valueTask))
                 {
@@ -111,9 +109,9 @@ internal Task<IRpcWorkerChannel> GetChannelAsync(string language)
             return Task.FromResult<IRpcWorkerChannel>(null);
         }
 
-        public Dictionary<string, TaskCompletionSource<IRpcWorkerChannel>> GetChannels(string language)
+        public IDictionary<string, TaskCompletionSource<IRpcWorkerChannel>> GetChannels(string language)
         {
-            if (!string.IsNullOrEmpty(language) && _workerChannels.TryGetValue(language, out Dictionary<string, TaskCompletionSource<IRpcWorkerChannel>> workerChannels))
+            if (!string.IsNullOrEmpty(language) && _workerChannels.TryGetValue(language, out ConcurrentDictionary<string, TaskCompletionSource<IRpcWorkerChannel>> workerChannels))
             {
                 return workerChannels;
             }
@@ -237,7 +235,7 @@ public Task<bool> ShutdownChannelIfExistsAsync(string language, string workerId,
 
             if (_hostingConfigOptions.Value.RevertWorkerShutdownBehaviour)
             {
-                if (_workerChannels.TryRemove(language, out Dictionary<string, TaskCompletionSource<IRpcWorkerChannel>> rpcWorkerChannels))
+                if (_workerChannels.TryRemove(language, out ConcurrentDictionary<string, TaskCompletionSource<IRpcWorkerChannel>> rpcWorkerChannels))
                 {
                     if (rpcWorkerChannels.TryGetValue(workerId, out TaskCompletionSource<IRpcWorkerChannel> value))
                     {
@@ -264,7 +262,7 @@ public Task<bool> ShutdownChannelIfExistsAsync(string language, string workerId,
             }
             else
             {
-                if (_workerChannels.TryGetValue(language, out Dictionary<string, TaskCompletionSource<IRpcWorkerChannel>> rpcWorkerChannels)
+                if (_workerChannels.TryGetValue(language, out ConcurrentDictionary<string, TaskCompletionSource<IRpcWorkerChannel>> rpcWorkerChannels)
                     && rpcWorkerChannels.TryRemove(workerId, out TaskCompletionSource<IRpcWorkerChannel> value))
                 {
                     value?.Task.ContinueWith(channelTask =>
@@ -304,7 +302,7 @@ internal void ScheduleShutdownStandbyChannels()
                         using (_metricsLogger.LatencyEvent(string.Format(MetricEventNames.SpecializationShutdownStandbyChannels, runtime.Key)))
                         {
                             _logger.LogInformation("Disposing standby channel for runtime:{language}", runtime.Key);
-                            if (_workerChannels.TryRemove(runtime.Key, out Dictionary<string, TaskCompletionSource<IRpcWorkerChannel>> standbyChannels))
+                            if (_workerChannels.TryRemove(runtime.Key, out ConcurrentDictionary<string, TaskCompletionSource<IRpcWorkerChannel>> standbyChannels))
                             {
                                 foreach (string workerId in standbyChannels.Keys)
                                 {
@@ -338,7 +336,7 @@ public async Task ShutdownChannelsAsync()
             foreach (string runtime in _workerChannels.Keys)
             {
                 _logger.LogInformation("Shutting down language worker channels for runtime:{runtime}", runtime);
-                if (_workerChannels.TryRemove(runtime, out Dictionary<string, TaskCompletionSource<IRpcWorkerChannel>> standbyChannels))
+                if (_workerChannels.TryRemove(runtime, out ConcurrentDictionary<string, TaskCompletionSource<IRpcWorkerChannel>> standbyChannels))
                 {
                     foreach (string workerId in standbyChannels.Keys)
                     {
@@ -378,13 +376,13 @@ internal void AddOrUpdateWorkerChannels(string initializedRuntime, IRpcWorkerCha
             _workerChannels.AddOrUpdate(initializedRuntime,
                     (runtime) =>
                     {
-                        Dictionary<string, TaskCompletionSource<IRpcWorkerChannel>> newLanguageWorkerChannels = new Dictionary<string, TaskCompletionSource<IRpcWorkerChannel>>();
-                        newLanguageWorkerChannels.Add(initializedLanguageWorkerChannel.Id, new TaskCompletionSource<IRpcWorkerChannel>());
+                        ConcurrentDictionary<string, TaskCompletionSource<IRpcWorkerChannel>> newLanguageWorkerChannels = new(StringComparer.OrdinalIgnoreCase);
+                        newLanguageWorkerChannels.TryAdd(initializedLanguageWorkerChannel.Id, new TaskCompletionSource<IRpcWorkerChannel>());
                         return newLanguageWorkerChannels;
                     },
                     (runtime, existingLanguageWorkerChannels) =>
                     {
-                        existingLanguageWorkerChannels.Add(initializedLanguageWorkerChannel.Id, new TaskCompletionSource<IRpcWorkerChannel>());
+                        existingLanguageWorkerChannels.TryAdd(initializedLanguageWorkerChannel.Id, new TaskCompletionSource<IRpcWorkerChannel>());
                         return existingLanguageWorkerChannels;
                     });
         }
@@ -392,7 +390,7 @@ internal void AddOrUpdateWorkerChannels(string initializedRuntime, IRpcWorkerCha
         internal void SetInitializedWorkerChannel(string initializedRuntime, IRpcWorkerChannel initializedLanguageWorkerChannel)
         {
             _logger.LogDebug("Adding webhost language worker channel for runtime: {language}. workerId:{id}", initializedRuntime, initializedLanguageWorkerChannel.Id);
-            if (_workerChannels.TryGetValue(initializedRuntime, out Dictionary<string, TaskCompletionSource<IRpcWorkerChannel>> channel))
+            if (_workerChannels.TryGetValue(initializedRuntime, out ConcurrentDictionary<string, TaskCompletionSource<IRpcWorkerChannel>> channel))
             {
                 if (channel.TryGetValue(initializedLanguageWorkerChannel.Id, out TaskCompletionSource<IRpcWorkerChannel> value))
                 {
@@ -404,7 +402,7 @@ internal void SetInitializedWorkerChannel(string initializedRuntime, IRpcWorkerC
         internal void SetExceptionOnInitializedWorkerChannel(string initializedRuntime, IRpcWorkerChannel initializedLanguageWorkerChannel, Exception exception)
         {
             _logger.LogDebug("Failed to initialize webhost language worker channel for runtime: {language}. workerId:{id}", initializedRuntime, initializedLanguageWorkerChannel.Id);
-            if (_workerChannels.TryGetValue(initializedRuntime, out Dictionary<string, TaskCompletionSource<IRpcWorkerChannel>> channel))
+            if (_workerChannels.TryGetValue(initializedRuntime, out ConcurrentDictionary<string, TaskCompletionSource<IRpcWorkerChannel>> channel))
             {
                 if (channel.TryGetValue(initializedLanguageWorkerChannel.Id, out TaskCompletionSource<IRpcWorkerChannel> value))
                 {
diff --git a/test/WebJobs.Script.Tests/Workers/Rpc/TestRpcWorkerChannelManager.cs b/test/WebJobs.Script.Tests/Workers/Rpc/TestRpcWorkerChannelManager.cs
index c7f87df462..fe3a3187e9 100644
--- a/test/WebJobs.Script.Tests/Workers/Rpc/TestRpcWorkerChannelManager.cs
+++ b/test/WebJobs.Script.Tests/Workers/Rpc/TestRpcWorkerChannelManager.cs
@@ -35,7 +35,7 @@ public IRpcWorkerChannel GetChannel(string language)
             throw new System.NotImplementedException();
         }
 
-        public Dictionary<string, TaskCompletionSource<IRpcWorkerChannel>> GetChannels(string language)
+        public IDictionary<string, TaskCompletionSource<IRpcWorkerChannel>> GetChannels(string language)
         {
             if (_workerChannels.TryGetValue(language, out Dictionary<string, TaskCompletionSource<IRpcWorkerChannel>> workerChannels))
             {
diff --git a/test/WebJobs.Script.Tests/Workers/Rpc/WebHostRpcWorkerChannelManagerTests.cs b/test/WebJobs.Script.Tests/Workers/Rpc/WebHostRpcWorkerChannelManagerTests.cs
index 2ee6adbe38..4382ca4867 100644
--- a/test/WebJobs.Script.Tests/Workers/Rpc/WebHostRpcWorkerChannelManagerTests.cs
+++ b/test/WebJobs.Script.Tests/Workers/Rpc/WebHostRpcWorkerChannelManagerTests.cs
@@ -4,6 +4,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.Azure.WebJobs.Script.Config;
 using Microsoft.Azure.WebJobs.Script.Description;
@@ -407,6 +408,38 @@ public async Task ShutdownChannelsIfExist_Succeeds()
             Assert.Null(initializedChannel);
         }
 
+        [Fact]
+        public void ShutdownChannelsIfExist_Race_Succeeds()
+        {
+            var channel = CreateTestChannel(RpcWorkerConstants.JavaLanguageWorkerName);
+            string id = channel.Id;
+
+            List<Task<bool>> tasks = new();
+            List<Thread> threads = new();
+            for (int i = 0; i < 2; i++)
+            {
+                Thread t = new(static (state) =>
+                {
+                    var (channelManager, tasks, id) = ((WebHostRpcWorkerChannelManager, List<Task<bool>>, string))state;
+                    tasks.Add(channelManager.ShutdownChannelIfExistsAsync(RpcWorkerConstants.JavaLanguageWorkerName, id));
+                });
+                threads.Add(t);
+            }
+
+            foreach (Thread t in threads)
+            {
+                t.Start((_rpcWorkerChannelManager, tasks, id));
+            }
+
+            foreach (Thread t in threads)
+            {
+                t.Join();
+            }
+
+            // only one should successfully shut down
+            Assert.Single(tasks, t => t.Result == true);
+        }
+
         [Fact]
         public async Task ShutdownChannelsIfExistsAsync_StopsWorkerInvocations()
         {