Two seems to be the limit. If you log in to a third device / browser, you get logged out of everything else, but if you log back in only on one, it's fine again.
For example, when work blocked me the other week, I logged in via phone. When I got home, I had to log in to my computer again. But as long as I don't log in anywhere else -- including Tapatalk on the same phone -- I'm fine.
Is that your issue, or does it seem to be something else?
It also might be a cache problem or a blocker setting problem, as others have suggested. Try forcing a reload. (E.g. ctl-shift-R)