I Use same mesh in Substance Painter and in Unreal Engine 4.20, but in engine seams become more visible
in substance:
in SP i use OpenGL
Baked in Marmoset with
Normally when I see this I first check if it is not a seam produced by a bad UV map, next I check if the textured edges are not exactly overlapping with the UV edges. Sometimes software misbehaves when they do and in general it is advised to paint / stretch a bit over the UV edges.