Almost transparent box appears on screen when scrolling through topics

[Flightistic]

When I am scrolling through topics this strange box appears:

(near the center you can see it)
I does not appear in any other apps or on my phone.

I am currently running Windows 10 Pro build 19043.

I have already tried clearing my cache and cookies, and it has not changed anything.

Any help is appreciated :)

[CaptainRyan]

It might be your computer monitor or something, I don’t see it in the picture.

[Flightistic]

Yeah, I just checked the picture on my phone and I can’t see anything.

Flagged for closure