[SR-Users] force_send_socket - multiple times per dialog, subsequent times fail

I am having an issue with 1.5.4 where force_send_socket() isn't behaving as I would expect. I have an LCR scenario where depending on which gateway I am sending to, I send from a different socket. It appears that calling force_send_socket from failure_route has no affect on the routing. In my initial route block I call force_send_socket(X.X.X.180:5060). In my failure_route I am calling force_send_socket(X.X.X.179:5060), yet after calling the subsequent time, my sip trace and tcpdump are clearly showing kamailio is still sending from X.X.X.180:5060. I have added a lot of debug lines, so I am 100% sure the second call to force_send_socket is happening. Am I misusing this module in some way?