Who knows how to fix this?

[Hahonator]

It's when the background of the round ending/round beginning gets all pixelated and shows textures.

 

[Vertago]

Ya have the steam Version? If so then re validate your files. If not, reinstall.

 

[Howl Pendragon]

Try downloading the latest drivers/updates for your graphics card. That fixed a lot of the issues for me