if i use displacements (PF shader) on fake stones surface shader inputs i get these artifacts in the background (middle render in picture below)
this preset uses multiple fake stones shader nodes and merge shaders, i have found turning off merge displacements gets rid of the artifacts but changes the way they look
it only seems to do this with fractal terrains, heightfields and flat terrain look normal
Try bringing up your smallest scales in the PF's until the effect goes away (or lowering the octaves). I think some of the internal smallest scales may have changed over the last few years.
Just make sure that none of the shaders are using a scale smaller than 0.01.
- Oshyan
ok, thanx oshyan/cyphyr seems i fixed it :)