I consistently have to log into the admin panel on v1.2 beta 3. I haven't updated yet but I only noticed it after going from 1.1.5 to 1.2 beta 3. Sometimes I can browse that admin panel with no problem, other times every link I click I have to relogin.
I forget the host off hand, but I did see a server where the IP of the client was sporadically changing because of some sort of reverse proxy system. The IP that came up was a CloudFlare IP but adding the standard workaround didn't totally help.
If your host is doing something like this, you may need to contact them for guidance. They really should try to tackle this at the server level as it would affect fundamental things like web server logs, not to mention apps installed on top (like XF).