Why does my normal map create these weird "stains"?

why does my model get these weird shading problems when applied normal map baked in substance painter? the problem mainly occurs on the parts that include 90 degree angles. (model made in maya)

things i’ve tried: reimport, harden edges on both exploded mesh and normal mesh, rebake with different settings. built lighting

it looks fine in substance painter and fine in UE4 without normal map but totally just breaks down then normal map is applied.
thanks!

why don’t you circle or draw an arrow to what you’re referencing? I don’t see it. That shadow is super dark, it’s full black. It could be a lighting problem.