Logging screen Picture Bug [client?]

The picture in my logging screen is smaller and there is a huge black part from top right to botom left in the for of a J. i have a picture attach to show. This bug happen since Braum logging screen and only if the animation is on (if i remove the annimation it goes back normal, and if i put it back it goe back with the black J shape) it doesn't stop me from playing, but i believe it is quite annoying