SP does something wrong to my mesh when recomputing normals.

I have a very high-res mesh from Zbrush. When importing into SP, I got the error:

Mesh normals are invalid (some values are null) and will be recomputed.

When I reopen the saved scene, SP will crash.

I checked in Zbrush; I checked in Maya; I checked in Meshlab. I couldn't find any errors. in my mesh. As a hack I re-exported the mesh again after SP recalculated the normals. This worked- I can reopen the saved scene.

However it did something to the mesh. It looks like a UV-mistake; although the UVs are the same..

What is going on here? Please help....