diff --git a/src/InformaticsGateway/Services/Export/ExportServiceBase.cs b/src/InformaticsGateway/Services/Export/ExportServiceBase.cs
index 00b5f4b0..d7f36fdc 100644
--- a/src/InformaticsGateway/Services/Export/ExportServiceBase.cs
+++ b/src/InformaticsGateway/Services/Export/ExportServiceBase.cs
@@ -53,6 +53,8 @@ public abstract class ExportServiceBase : IHostedService, IMonaiService, IDispos
     {
         protected static readonly object SyncRoot = new();
 
+        protected static string BuildExportKey(string workflowInstanceId, string exportTaskId) => $"{workflowInstanceId}/{exportTaskId}";
+
         internal event EventHandler? ReportActionCompleted;
 
         private readonly CancellationTokenSource _cancellationTokenSource;
@@ -373,7 +375,7 @@ private static void HandleStatus(ExportRequestDataMessage exportRequestData, Exp
 
         private void ReportingActionBlock(ExportRequestDataMessage exportRequestData)
         {
-            var exportRequest = ExportRequests[exportRequestData.ExportTaskId];
+            var exportRequest = ExportRequests[BuildExportKey(exportRequestData.WorkflowInstanceId, exportRequestData.ExportTaskId)];
             HandleStatus(exportRequestData, exportRequest);
             if (!exportRequest.IsCompleted)
             {
@@ -391,7 +393,7 @@ private void ReportingActionBlock(ExportRequestDataMessage exportRequestData)
 
             lock (SyncRoot)
             {
-                ExportRequests.Remove(exportRequestData.ExportTaskId);
+                ExportRequests.Remove(BuildExportKey(exportRequestData.WorkflowInstanceId, exportRequestData.ExportTaskId));
             }
 
             if (ReportActionCompleted != null)
@@ -588,7 +590,8 @@ protected async Task BaseProcessMessage(MessageReceivedEventArgs eventArgs)
             lock (SyncRoot)
             {
                 var exportRequest = eventArgs.Message.ConvertTo<ExportRequestEvent>();
-                if (ExportRequests.ContainsKey(exportRequest.ExportTaskId))
+                string exportKey = BuildExportKey(exportRequest.WorkflowInstanceId, exportRequest.ExportTaskId);
+                if (ExportRequests.ContainsKey(exportKey))
                 {
                     _logger.ExportRequestAlreadyQueued(exportRequest.CorrelationId, exportRequest.ExportTaskId);
                     return;
@@ -599,7 +602,7 @@ protected async Task BaseProcessMessage(MessageReceivedEventArgs eventArgs)
 
                 var exportRequestWithDetails = new ExportRequestEventDetails(exportRequest);
 
-                ExportRequests.Add(exportRequest.ExportTaskId, exportRequestWithDetails);
+                ExportRequests.Add(exportKey, exportRequestWithDetails);
                 if (!exportFlow.Post(exportRequestWithDetails))
                 {
                     _logger.ErrorPostingExportJobToQueue(exportRequest.CorrelationId, exportRequest.ExportTaskId);
diff --git a/src/InformaticsGateway/Services/Export/ExtAppScuExportService.cs b/src/InformaticsGateway/Services/Export/ExtAppScuExportService.cs
index fb602be5..552df302 100755
--- a/src/InformaticsGateway/Services/Export/ExtAppScuExportService.cs
+++ b/src/InformaticsGateway/Services/Export/ExtAppScuExportService.cs
@@ -67,7 +67,8 @@ protected override async Task ProcessMessage(MessageReceivedEventArgs eventArgs)
             lock (SyncRoot)
             {
                 var externalAppRequest = eventArgs.Message.ConvertTo<ExternalAppRequestEvent>();
-                if (ExportRequests.ContainsKey(externalAppRequest.ExportTaskId))
+                string exportKey = BuildExportKey(externalAppRequest.WorkflowInstanceId, externalAppRequest.ExportTaskId);
+                if (ExportRequests.ContainsKey(exportKey))
                 {
                     _logger.ExportRequestAlreadyQueued(externalAppRequest.CorrelationId, externalAppRequest.ExportTaskId);
                     return;
@@ -78,7 +79,7 @@ protected override async Task ProcessMessage(MessageReceivedEventArgs eventArgs)
 
                 var exportRequestWithDetails = new ExportRequestEventDetails(externalAppRequest);
 
-                ExportRequests.Add(externalAppRequest.ExportTaskId, exportRequestWithDetails);
+                ExportRequests.Add(exportKey, exportRequestWithDetails);
                 if (!exportFlow.Post(exportRequestWithDetails))
                 {
                     _logger.ErrorPostingExportJobToQueue(externalAppRequest.CorrelationId, externalAppRequest.ExportTaskId);
diff --git a/src/InformaticsGateway/Test/Services/Export/ExportServiceBaseTest.cs b/src/InformaticsGateway/Test/Services/Export/ExportServiceBaseTest.cs
index afdb3e6f..717326a2 100755
--- a/src/InformaticsGateway/Test/Services/Export/ExportServiceBaseTest.cs
+++ b/src/InformaticsGateway/Test/Services/Export/ExportServiceBaseTest.cs
@@ -81,7 +81,8 @@ protected override async Task ProcessMessage(MessageReceivedEventArgs eventArgs)
             lock (SyncRoot)
             {
                 var exportRequest = eventArgs.Message.ConvertTo<ExportRequestEvent>();
-                if (ExportRequests.ContainsKey(exportRequest.ExportTaskId))
+                string exportKey = BuildExportKey(exportRequest.WorkflowInstanceId, exportRequest.ExportTaskId);
+                if (ExportRequests.ContainsKey(exportKey))
                 {
                     return;
                 }
@@ -91,7 +92,7 @@ protected override async Task ProcessMessage(MessageReceivedEventArgs eventArgs)
 
                 var exportRequestWithDetails = new ExportRequestEventDetails(exportRequest);
 
-                ExportRequests.Add(exportRequest.ExportTaskId, exportRequestWithDetails);
+                ExportRequests.Add(exportKey, exportRequestWithDetails);
                 if (!exportFlow.Post(exportRequestWithDetails))
                 {
                     MessageSubscriber.Reject(eventArgs.Message);
@@ -342,6 +343,62 @@ public async Task DataflowTest_EndToEnd()
             _outputDataPlugInEngine.Verify(p => p.ExecutePlugInsAsync(It.IsAny<ExportRequestDataMessage>()), Times.Exactly(5 * 2));
         }
 
+        [RetryFact(1, 10, DisplayName = "Data flow test - same ExportTaskId different WorkflowInstanceId are not deduplicated")]
+        public async Task DataflowTest_SameExportTaskId_DifferentWorkflowInstanceId_BothProcessed()
+        {
+            var sharedExportTaskId = Guid.NewGuid().ToString();
+            var completedCount = 0;
+
+            _messagePublisherService.Setup(p => p.Publish(It.IsAny<string>(), It.IsAny<Message>()));
+            _messageSubscriberService.Setup(p => p.Acknowledge(It.IsAny<MessageBase>()));
+            _messageSubscriberService.Setup(p => p.RequeueWithDelay(It.IsAny<MessageBase>()));
+            _messageSubscriberService.Setup(
+                p => p.SubscribeAsync(It.IsAny<string>(),
+                                 It.IsAny<string>(),
+                                 It.IsAny<Func<MessageReceivedEventArgs, Task>>(),
+                                 It.IsAny<ushort>()))
+                .Callback<string, string, Func<MessageReceivedEventArgs, Task>, ushort>(async (topic, queue, messageReceivedCallback, prefetchCount) =>
+                {
+                    // Same ExportTaskId, two different WorkflowInstanceIds - must NOT be deduplicated
+                    await messageReceivedCallback(CreateMessageReceivedEventArgs(Guid.NewGuid().ToString(), sharedExportTaskId));
+                    await messageReceivedCallback(CreateMessageReceivedEventArgs(Guid.NewGuid().ToString(), sharedExportTaskId));
+                });
+
+            _storageService.Setup(p => p.GetObjectAsync(It.IsAny<string>(), It.IsAny<string>(), It.IsAny<CancellationToken>()))
+                .ReturnsAsync(new MemoryStream(Encoding.UTF8.GetBytes("test")));
+
+            var countdownEvent = new CountdownEvent(2);
+            var service = new TestExportService(_logger.Object, _configuration, _serviceScopeFactory.Object, _dicomToolkit.Object);
+            service.ReportActionCompleted += (sender, e) =>
+            {
+                Interlocked.Increment(ref completedCount);
+                countdownEvent.Signal();
+            };
+            await service.StartAsync(_cancellationTokenSource.Token);
+            Assert.True(countdownEvent.Wait(60000), $"Expected 2 exports to complete but only {completedCount} completed - second request was incorrectly deduplicated");
+            await StopAndVerify(service);
+
+            _messagePublisherService.Verify(
+                p => p.Publish(It.IsAny<string>(),
+                               It.Is<Message>(match => (match.ConvertTo<ExportCompleteEvent>()).Status == ExportStatus.Success)), Times.Exactly(2));
+            _messageSubscriberService.Verify(p => p.Acknowledge(It.IsAny<MessageBase>()), Times.Exactly(2));
+        }
+
+        internal static MessageReceivedEventArgs CreateMessageReceivedEventArgs(string workflowInstanceId, string exportTaskId)
+        {
+            var exportRequestEvent = new ExportRequestEvent
+            {
+                ExportTaskId = exportTaskId,
+                CorrelationId = Guid.NewGuid().ToString(),
+                Destinations = new[] { "destination" },
+                Files = new[] { "file1", "file2" },
+                MessageId = Guid.NewGuid().ToString(),
+                WorkflowInstanceId = workflowInstanceId,
+            };
+            var jsonMessage = new JsonMessage<ExportRequestEvent>(exportRequestEvent, MessageBrokerConfiguration.InformaticsGatewayApplicationId, exportRequestEvent.CorrelationId, exportRequestEvent.DeliveryTag);
+            return new MessageReceivedEventArgs(jsonMessage.ToMessage(), CancellationToken.None);
+        }
+
         internal static MessageReceivedEventArgs CreateMessageReceivedEventArgs()
         {
             var exportRequestEvent = new ExportRequestEvent