Beta client continuing to disappoint

I have no idea what the problem is, but the client lagged to an unbelievable degree whilst in champion select, and then everything went black like it was patching or something, with the L loading circle in the middle, and now it no longer allows me to click accept for games.

Restarting the client appears to have fixed the issue, for now, but better to present it so it can be fixed at some point.