Graphics - white line on the horizon

[Trax]

Can't figure out what's causing this, but I am getting a white line on the horizon. Happens in every zone, day, night, rain, or snow.

Windows 10, windowed mode, gpu RTX 480.

https://i.imgur.com/3iX2pUQ.jpeg
https://i.imgur.com/3iX2pUQ.jpeg