I am also having the Witcher 3 terrain rendering issue. It seems like the terrain is rendered at a different distance than objects on the terrain. There is also a similar problem with the graffiti on the walls at the inn at the start of the game. The graffiti seems to kind of float on the wall. I am using a fresh install of GOTY edition. Issue persists on Ultra and Low quality. I’m using a 1080 ti and HTC Vive.