Blank Screen on Champ Select [Client]

I accepted a match while in queue with a friend. His screen loaded showing the choices of Champions. While mine was a blank screen. I waited about a minute with nothing happening before I quit League.

1. Go into normal Queue with friend
2. Accept Match
3. Loads a blank screen (see link for screenshot)

This is the first time it has happened. Don't know whether I should report it, since it has only happened once. But here you go.