Cel shading looks very jagged

Hi,
I’m trying to create a cel shaded environment in the VR template. This tutorial was followed to set up the post processing effect: Unreal Engine 4 Cel Shading Tutorial | raywenderlich.com
This is the blueprint

It works great with simpler, geometric meshes. However, when I import this face, the shadows look terrible when I build the lighting. The preview light looks nice!

https://forums.unrealengine.com/filedata/fetch?filedataid=166789&type=thumb

https://forums.unrealengine.com/filedata/fetch?filedataid=166790&type=thumb

https://forums.unrealengine.com/filedata/fetch?filedataid=166791&type=thumb

Maybe there’s something wrong with the mesh, so that the light can’t be calculated properly?