Match Loding - Potentially Game Breaking

I was in the match-making lobby waiting on the game to start then i remembered to change my skin & masteries. (Everyone else had previously picked)

So then I continued to open up the skin selector and suddenly everything went all weird and I couldn't type in chat. I also couldn't change my masteries.

This is the first time it has happened to me; so I'm not sure if it's a 100% repro rate, but it kinda screwed me over earlygame, but thankfully it was just a norms.