Lync client failover timing question

Well this one has 7 people stumped, including 3 F5 engineers.

I'm tired from taking traces all day.

The last test we ran was really bizzare; with a client on a PC with a sniffer on it and controlling the servers, we verified the client was talking to the vip and the vip only. We pulled the plug on the server nic and watched the F5's know it's down, the http session for the client timed out right away but the sip-tls session stayed open a lot longer, about 2 minutes the client reconnected to the still up server. Now the strange part, when the old server was brought up, the client reconnected to it, but the sniffer trace showed the client was talking along to the never down server, then it went right out did a DNS lookup for the now brought up server (not the pool name)' it then connected directly to the newly up server bypassing the F5 all together.

So far we have verified dns, srv records, configs, etc. To me it looks like the client is somehow learning the individual server ip's and going direct to them, but we don't know how they are learning this. We have a ticket opened with MS, one with F5, and have had many guru's look at this. We are all stumped -stupid Lync :D

At this point there are nly two questions we really want to know;

What is the time it takes a client to reconnect through the F5's in a good setup (front end pool)?

And should the client ever have an individual host name in their Lync local file (client)?

Cheers,

Bob James