There is this persistent issue with LED Panels where the mapping repeats the first/last pixel in the extremities of the video wall.
The issue seems to happen in any type of mapping ("mapping to extents" & mapping by regions result in the same) and affects all image sources (NDI, video player, file source). Camera's angle definitely has an effect on this artifact, so depending on the way you are facing the panel, the issue become more/less present. Of course, it is most noticeable when displaying contents that have greater contrast between extremities (for example, a gradient that goes from white to pitch black).

I believe this comes from a bad setting in the program's way of handling the UVs / material for the LEDs. I might be mistaken, but this could be happening due to the material UVs being set to repeat (tiling enabled), or due to pixel interpolation. Maybe disable tiling for mapped materials (tiling = zero) and also disable pixel interpolation (texture filtering set to "nearest").

I would like to kindly ask the developers to look into this issue, I first noticed it in Capture 2024, and it has not been addressed yet.

I'm putting some images in the attachments to show it is present both in the viewport but also on the renders.