Hi,
My normal map goes wild on Unreal Engine 4, while on Blender/Marmoset therer’s no such thing. The edge looks like this in viewport:
https://i.imgur.com/d1BmyZk.png
And probably the troublemaker on the texture:
But as I said before, I don’t have that problem on different enviroments. Also smuding in Photoshop this area makes no difference.