Chained commands keep the same CommandId in nlog context

NzbDrone.Common/Messaging/MessageAggregator.cs

@@ -144,8 +144,11 @@ namespace NzbDrone.Common.Messaging
             var sw = Stopwatch.StartNew();
 
             try
+            {
+                if (!MappedDiagnosticsContext.Contains("CommandId"))
                 {
                     MappedDiagnosticsContext.Set("CommandId", trackedCommand.Command.CommandId);
+                }
 
                 PublishEvent(new CommandStartedEvent(trackedCommand));
                 handler.Execute(command);