multi tile normal maps problem

Skorn

so I've got this character I'm working on and I decided to use multi tile maps for a better close up resolution.
everything went fine, except for the normal maps.

https://www.dropbox.com/s/ebb680xxnt93r2c/Bor_arms_normals.tga?dl=0

it seems that xnormal rendered the faces of the lowpoly onto the details of the highpoly

anyone got an idea what went wrong?

thanks in advance