[GAMEPLAY] Screen goes black at random

I played an ARAM game and while I was playing, the game just went black. Sounds continued, game didn't freeze, just a black screen. All I saw was the League cursor. Just happened again in a normal game. Only happened once. I was Jhin, I went to ult, and my screen went black for about 2-3 seconds.

This has happened twice, both random, playing different modes with completely different teams. No idea how to recreate it. Probably wont help at all, but I'm also curious to see if this has happened to anyone else.