f0e2d7e5ca
This seems like a long-standing misuse of the custom vert normal APIs. It broke, obviously so, in 3.1 but 3.0 was also rather fragile as was noted in the original bug report. The `BKE_mesh_set_custom_normals_from_verts` should be the correct API to use when loading in vert normals from external files. The current code would yield faceted mesh shading, as-if there were no custom normals at all. Pull Request: https://projects.blender.org/blender/blender/pulls/130069