Hello Menelin,
I have ran into this in the past with Blender (never used substance), and the issue for me, was that I had not created the UVs inside of blender so they could be imported along with the mesh (even using the Smart UnWrap is fine). As well as, not Triangulating (this is not required, but I find that the mesh looks better) using the modifiers that blender has. Then finally to make sure all is well, have UE4 recompute the normals (Using the Mikk TSpace method).
So
- Edit mode in Blender, Select all (A key), then Smart Unwrap (U key)
- Export the object into FBX, (X forward, Z up)
- Then import into UE4, making sure that recompute nomals with Mikk TSpace selected.
When you are satisfied with the import, then go back, and do the triangulate, and re-import again. There is no need to mess around with all the extra faces/edges/verts that the triangulate will create, until you are totally satisfied with the mesh.
Hope this helps,