Printable View
https://youtu.be/FKOXNuiBDS8
In the first few seconds just two the right of my crossbar you'll notice the black box appear. During the entire video(a bit hard to tell) you'll notice my screen will randomly dim and brighten.
Not sure why this happens but it is super annoying.
That flickering looks more like something is trying to load or run in the background and keeps popping up like that.
Since I saw a menu pop up that looks like a PS4, I am assuming then you are not on a computer. I can say is see if anyone else has this issue with other apps running and this block box appears. Also check on what is installed and if anything is running in the background and if you can close it.
I play on a PC. So, I cannot help with more directions than these suggestions.