I finally managed to find a fix if you are having 2 skeleton meshes with morph targets and ZERO normal lighting issues! Have tested with multiple head types on the same body with ZERO lighting issues! 
Will write it up in the script🍻
This is a character with 2 skeleton meshes head & body separate with the head having morph targets and ZERO lighting issues around the neck seam!
This is the head just to show you it has morph targets.