[CRASH] Alt tab causing bugsplats

As the title suggests, alt tabbing before the loading screen renders champion portraits can occasionally cause the game to bugsplat. The game will then pull up a error message and refuse to connect until the game starts. After the game begins, you can reconnect normally. Until then, nothing will work. This doesn't seem to be a patch 6.22 specific issue, although it did begin a few patches back(not sure which one exactly)

Reproduction

1. Join a game.
2. Alt tab immediately after the client closes(right after champ select finishes) and as the game window(loading screen) appears.
3. Game will occasionally bugsplat and refuse connection.

I haven't taken numbers yet but I would say it occurs in about 20% of my games(I alt tab out quite frequently before games)

Crappy video of the aftermath(didn't think to record while I was attempting to reproduce)

Note: I swear I posted this exact issue earlier but couldn't find it when I was looking for it. Sorry if I double-posted.