**System Information**
Operating system: Windows-10-10.0.19041-SP0 64 Bits
Graphics card: NVIDIA GeForce GTX 1080 with Max-Q Design/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 465.89
**Blender Version**
Broken: version: 2.93.0 Alpha, branch: master, commit date: 2021-04-09 21:26, hash: `rB0515ff70ec09`
**Short description of error**
{F9926333}
Ok hints on this one:
The problem seems to be related to the custom split normals AND the sharp edges (this mesh has been imported from an alembic file)
Turning off Ambient Occlusion gets rid of the problem
**Exact steps for others to reproduce the error**
Open file
{F9926336}