Weird gray glitch from green screens/overlay

[imcryingfr]

Hi, every time I use a green screen/overlay a video on top of my main video, I get this weird error that makes the screen look like this for about a 0.5 second. It comes on when I use the green screen/overlay video but stays even when removing the green screen/overlay. I've tried to do so many things to fix this that it might just be my graphics card (rx 580). If anyone knows how to fix this, I would sincerely appreciate it.

In the image below I used a anime speed video overlay that caused this to happen.