We have the same object 2 materials. We can’t figure out what is wrong with the top material to make it do this. Suggestions would be great, the lower material is pretty basic, the upper material is very unique. I can see about getting the material screenshot later, just looking to see if I missed something really simple somewhere.
We’ve identified where the issue lies, just not why. It’s in the normal map somewhere. The normal map it’self works fine, we tested it on another material, we tested out a working normal map. Any normal map applied to material causes the lighting issue.
Solved, Calculate Normal Tangets got unchecked in the material itself.
Just a random guess:
Maybe your normal map is not tangent space but world space?
€dit: just a few seconds late 