Like a gray silhouette of the thing that was there.
It started happening a couple of days ago, or at least that's when i started noticing it.
Is there a setting that I can tune to make it go away or something?
I'm using a mi box s with Android 8.1.
Also I tried the same videos with the TV's own player and no such problem there.
It's your TV, and the only thing to do is perhaps try to put it into Sport mode, if it has one.
It's called ghosting due to slow response time of your tv. The pixels of your tv cannot switch from color to black fast enough. Try to move the image slowly and you will not see ghosting.
i looked up ghosting on my specific tv and found that power cycling both the tv and the mi box actually fixed it. i hope it as a one-time problem, thank you all for the comments.
I think that's due to your TV. Happens to me on my FireStick as well.