Unable to purge cache (ext & acp)

Hello!
Sometimes cache fails to clear when enabling/disabling ext. It results in a timeout on larger boards. Here is one example (its not easy to reproduce)

http://prnt.sc/ewdvg5 results in this: http://prnt.sc/ewdvlo

As for extensions sometimes when enabling or disabling them hangs. It loads until times out or goes to blank page. I have decent execution time settings and others but it still sometimes hangs on larger boards.