Invalid response format generates timeout

Hello,

Today I found a strange behavior in SoapUI when testing a web service that returned an incorrect response. Note the duplicate error message at the top and the bottom of the response:

As you can see, the top message is placed before the HTTP status code. This makes SoapUI to keep waiting as if there was no response and then give up with a timeout error. Is this a bug in SoapUI or it is the expected behavior by design?

Thanks,

Miguel