[CLIENT] Champ select constantly freezing up / not displaying things

This has happened to me on several occasions before, but this time I've had it twice in a row and it's really annoying, making me have to dodge games. Unfortunately no screenshots (too frantic trying to get a champ picked to think about screenshots) but I'll add some in when it happens again, which it inevitably will.

While in the banning phase, my last ban was LeBlanc. After I clicked her to ban her, her abilities stayed showing across the chat portion of the screen. Then when I was supposed to be picking a champion, the part usually showing your champion pool was completely empty and it ended up sticking me with Ezreal since I was completely unable to choose a champion.

The game before that, I couldn't select a champion even when I could see them all. I clicked on them, nothing happened, then when I tried to click on other champions it wouldn't do anything. I could still change summoner spells and runes/masteries, but it seemed as though my champ picks weren't working. Next thing I know, it seems to work again as I click all over the screen on a whole bunch of different champions. But after the first one shows up, I get a kind of loading thing and it won't let me switch to anyone else or change any of my spells etc until after the timer has already run out and I'm stuck yet again with either playing a random champ or dodging.

Has happened in all game modes, but seems to happen A LOT more in custom games.

Not a connectivity issue, because I can still hear the noise for messages being received even when the screen is covered by ability descriptions being stuck.

I'm on OCE, but we're not important enough to get our own bug report section so here I am.