Specular in UE4 is a legacy thing, it's not really supposed to be used. Have you worked with adjusting roughness? Because the specular intensity is directly tied to roughness.
Anyone? This illumination happens after baking lightmass. Seems the mesh was corrupt. Deleted it and remodelled it from a new primitive. Worked the way it should in ue4.
If you import the FBX back into Maya, are the normals correct? I don't work with animation, but these settings work for retaining correct normals in Marmoset and UE4.