Strage visual bug on FBX character w/ facial blends

Trying to import a character model with facial blend shapes. Original pipeline: hi-poly from Zbrush-> low-poly w/rig, weights and blends in blender → FBX export → import into UE4 as skeletal mesh.

In the attached image on the left is the character with no facial blends and a low poly face, on the right is the higher poly head with facial blends.

I get a strange shadow, no clue what is causing this.

Fixed: I went back into the original blender file, set up the project and model to scale correctly to UE4 settings and then specifically set FBX output options using the new Blender 2.7. Everything works fine now.