This was what was happening and how we resolved it: The load balancer and the back-end server were not able to agree on a cipher to use for the SSL handshake, so BigIP sent the redirect back to the client. After we enabled a cipher on the server that BigIP was using, the SSL handshake completed successfully, no redirection occurred, the HTTP POST went through to the server successfully, and a normal response was returned to the client. Btw, I used the term "SSL Termination" in this issue, but should have been using the term "SSL Bridging", since we were required to have SSL between the load balancer and the server, as well as between the client and the load balancer.
