so today I updated to 4.0 (glad I had backup).
Everything was working fine until I tried to publish a post. There I got
Are you sure you want to do this. Also had
Cheatin' Uh under appearance->customize. Very informative messages indeed. I turned to google and after some googling and experiments with enabling/disabling plugins I found out which one was causing it.
It was WP phpBB Bridge. It's plugin which allows users to login into WP with accounts of phpBB. After some search through code of that plugin I found that problem is caused by
load_session_id() function in
wp_set_auth_cookie($userid, true, false); line. If I comment that line out while logged in, problem will be solved alas it can hardly be called a solution. If I log out, I obviously won't be able to log in due not getting auth cookie.
And so, I'm stuck and have no clue how to solve this problem.