Problem developing WF4 application - The requested resource has moved to the one of the following locations

I am developing a WF4 application. The workflows are hosted in an ASP.NET website. For development, I am using IIS express.

When debugging between edit cycles I get this error:

System.ServiceModel.FaultException`1 was unhandled by user code
  Message=The requested resource has moved to the one of the following locations:
    https://localhost:44305/Workflows/PerformanceAppraisal/Exempt.xamlx
  StackTrace:
       at System.ServiceModel.Channels.ServiceChannel.ThrowIfFaultUnderstood(Message reply, MessageFault fault, String action, MessageVersion version, FaultConverter faultConverter)
       at System.ServiceModel.Channels.ServiceChannel.HandleReply(ProxyOperationRuntime operation, ProxyRpc& rpc)
       at System.ServiceModel.Channels.ServiceChannel.EndCall(String action, Object[] outs, IAsyncResult result)
       at System.ServiceModel.ClientBase`1.ChannelBase`1.EndInvoke(String methodName, Object[] args, IAsyncResult result)
       at GoodwillHR.ExemptPAService.ExemptPAClient.ExemptPAClientChannel.EndGetSelfAppraisalForEmployeeUpdate(IAsyncResult result)
       at GoodwillHR.Exempt开发者_开发技巧PAService.ExemptPAClient.GoodwillHR.ExemptPAService.IExemptPA.EndGetSelfAppraisalForEmployeeUpdate(IAsyncResult result)
       at GoodwillHR.ExemptPAService.ExemptPAClient.EndGetSelfAppraisalForEmployeeUpdate(IAsyncResult result)
       at GoodwillHR.ExemptPAService.ExemptPAClient.OnEndGetSelfAppraisalForEmployeeUpdate(IAsyncResult result)
       at System.ServiceModel.ClientBase`1.OnAsyncCallCompleted(IAsyncResult result)
  InnerException: 

What is the problem?

Some more info: XAMLX workflow with multiple receives. Content correlation is set up correctly as everything works fine if I don't stop the debugger.

I am getting the error after I stop the debugger, start debugging again and then call one of the workflow receive activities on a persisted workflow.

Not sure why, but doing a service reference update made this problem go away. I didn't think I had any changes in my workflow service.