[CLIENT] client fails to load following a match

So, after a game, usually ranked since that's what I play but can be normals too, the client will just fail to load. The client has in fact exited, seeing as how I have to log back in. I don't really care so much except now I can't see any of my mastery scores, so that's annoying.

I have no idea how to reproduce this bug. I cannot predict it. Hell, I don't even know it's going to happen until I end the match. I mean, I can't really provide screenshots of it either, since it's just my desktop. Game ends. back to desktop. Have to log in again.