I have no idea how to describe it better. See it by yourself.
On this slope, you are able to see the sand sort of model mesh, move by itself when you either go down, or up the slope.
I think the game does this to save frames? I do not know…
Probably not a frame saving feature, especially when it makes a simple slope geometry more complex due to it, and is extremely visible despite playing with Ultra settings.
I’ll go with more of some UE4 shenanigans.
It’s UE4 doing automatic terrain LODs for optimization. Regardless, I will be updating this when the map gets its polishing pass.