[PVP.net] Black screen while first pick in ranked queue

This only happens to me very rarely, perhaps once out of 100 games. But it is always in ranked, and I see for a fraction of a second I am first pick when it happens (Right as the client makes the noise for me to take my first ban - I imagine this bit of info is helpful)... and then all the sudden most of my client goes black and I cant pick a champion. This has costed me a promo, and a few other random LP.

There are no crash logs to post - because my client is still "working", and hasn't crashed.