Hey,
I am not sure what could be happenning, but, it could be caused because you are creating a new task client and hornetq connectors each time. So maybe the response is taken (in class HornetQTaskClientConnector) for some the last (or first?) connector (and thud task client handler) you created, and may lead to problems.
Could you change your code to cache this task client in createHornetQTaskClient method for example and see what happens?
Thanks
Demian