How to hide stroke in viewportframe

I ran into an unexpected problem: for some reason, a character located in a ViewportFrame with a WorldModel has a strange light outline around it.
Well, in general, I need to somehow remove it.

Thank you!

You can’t hide it sadly. But you can change this stroke color, to match other GUIs background colors. To do it, change ViewportFrame.BackgroundColor3.

How could yall achieve that problem, I encountered no such outline

Yes, this is the essence of what I have, and no one else has