MockService becomes unstable when deleting Requests in the UI

Whenever I delete requests from a SOAP Interface or REST Method in the UI, while also running a MockService, I soon start seeing errors in the Error Log (org.apache.xmlbeans.impl.values.XmlValueDisconnectedException), and the MockService behavior becomes unstable and unpredictable. For example, it may respond with errors or fail to respond.

I encounter this a lot at work computer and related projects (SoapUI OS 5.3.0) and I can easily reproduce the problem at home from an empty project (SoapUI OS 5.4.0). For example:

1. Add any WSDL with one or more SOAP operations - SoapUI Tutorial WSDL, perhaps - and a new Request.

2. Create a MockService and add a SOAP operation.

3. Start the MockService.

4. Clone the Request, then delete the clone

5. Send requests to local MockService

(may need to repeat steps 4 and 5 just a few times to see the errors in the Error Log).

Is there some best practice I am missing? For example, is this happening because I am not always stopping the MockService before making changes to the Interface/Requests in the UI?

I think that this problem only occurs when making changes via the UI. I don't run into the same problem when deleting requests via a script while a MockService is running i.e.

WsdlOperation.removeRequest(WsdlRequest request)