Intermittent issues with APM

I am not sure if I am posting in the write forum but I will try to ask the question anyways. We have just recently deployed F5 APM in our environment. The architecture design of our environment is such that we have two F5 device, one F5 LTM that is sitting on the DMZ handling external traffic and another one internal that we deployed APM for authentication. We configured the virtual server/pool to point to the virtual server sitting internally in the APM which has the Access policy enabled.

The configuration of our APM is somewhat similar to what is posted in this article.

http://devcentral.f5.com/wiki/APM.MultipleNTLMSSO.ashx

Earlier on, we had some issues with oneconnect profile enabled on the external virtual server but when we disabled it, it seem to work. This is because oneconnect was trying to share connection and this does not work well with APM. The problem users will encounter is that after user logins and is in the middle of the session, user will get booted back to the login screen and will have to login again. But when we look at the APM report screen, we see that the old session still exists.

But now once we implemented into production, we again are running into the same intermittent issue where by user will lose session but the old session would still exist. This time though it happens not very frequently. The problem now though is that this issue is hard to re-create. It work all the time in our test environment but in production, we get intermittent issue. There are no logs we could find that would help us troubleshoot this issue.

My question to this post is that have anyone tried deploying F5 APM behind a proxy which in our case another LTM? And if there is, is there a recommended setting that needs to be set. I somehow still is suspicious that this is causing the issue because the user is not connecting directly to the APM device.

Thanks in advance?