[Client] Game turned black, no music no sounds, durinc champion select

Joined the queue for an ARAM match, clicked Accept and Alt+Tabbed. Right after, there was a sound of a trade request, the window popped up and everything in the client turned black, with the background music stopped.

Unable to do anything about it, i tried to close the client. The "Are you sure you want to leave" message popped up, but without knowing the circumstances of the match, i couldn't risk waiting any longer so I quit. Upon reload, the leaver penalty was on.

I believe the double pop up of the client and the trade window somehow bugged the whole thing.