I thought it was my VPN connection not storing cookies right away, but it seems im not the only one. I have the feeling it happens more when u open the 3 buttons in the top (profile / inbox / alerts) after the initial login.
I just found out there is a apparently a bug if you come directly to the site from Facebook. It is a software bug (versus a site bug). They have patched the XenForo software and I will need to update the site software.
I don't know if you are experiencing the issue when coming here from Facebook, but as far as I'm concerned, any glitch that logs you out of the site is no good...
I was having a lot of trouble with the main page not completely loading and freezing. I never log out of the site and just click on it in my favorites. The ad on the left side of the main page illustrated the top right corner of the page (Alerts).
I opened a fresh IE iteration and that seemed to fix the problem. I saved this new page as a favorite.
It works much better for me now, i think you are right, it happens when i hover my profile page buttons, i see a small loading bar above the navigation panel (in the banner / far top right), which seems to fail and log me out.
I still have to log in more than once. Not coming from Facebook. I log in as usual and check remember me. If I go to Alerts then a second log in window appears and tells me I must be logged in to use that...... Have worked around be it is an irritant.
But your efforts and dedication to our ability to discuss this wonderful art form is greatly appreciated.