Vertex normals incorrect, but face normals look correct? I recently imported an FBX from a Max export and about 90% of the model looks fine but for some parts, the vertex normals are 'twisted' even though the face normals look correct. As far as I can tell the parts are all manifold and the bad mesh in the image below is just a simple cylinder so I don't think its possible for that to be non-manifold, right? Also when I tried to select non-manifold, nothing selected.

I added a new cylinder for reference and those verts look fine. How can i 'reset' the weird verts without remodelling these parts?
Those are probably custom normal data imported from 3Ds MAX

Try the Clear Custom Split Normals Data button in the Properties Window > Object Data Tab > Geometry Data Panel (It will only be visible if there is any actual custom normal data stored)