Every time I go to a different part of the site, I get logged out of all parts of the site. It logs me out when I answer a question sometimes too. And sometimes I am on chat, and it says I am not currently allowed to post. What the heck? This started yesterday.
I did recently do something to fix the old logout problems, where if you logged out of one section it kept you logged in to the others.
Try logging out of all sections now, then log in again and let me know if the issue continues.