What could be the problem of this?
It looks like overlapping meshes (sure there only one terrain object here ?), don’t you have more infos like a screenshot of your Unity main view ? Does this “effect” follows you or does it only appear in this place ?
It follows throughout the map itself on the mountains.
What would you like too see?
I’m totally not sure but maybe it comes from SUIMONO, have you tried things like de-activating dynamic reflections, caustic effects or reversing UVs from SUIMONO_Module ? SUIMONO doc if you haven’t already did.