System Information
Operating system: Windows-7-6.1.7601-SP1 64 Bits
Graphics card: GeForce 8800 GTS 512/PCIe/SSE2 NVIDIA Corporation 3.3.0
Blender Version
Broken: version: 2.90.1, branch: master, commit date: 2020-09-23 06:43, hash: rB3e85bb34d0d7
Worked: no version worked
Short description of error
any multimaterial will show glitchs and triangles on model , in viewport.
Exact steps for others to reproduce the error
add multiple materials and assign to diverse faces of a single mesh, showing triangles and glitchs.