Operating system: Darwin-19.5.0-x86_64-i386-64bit 64 Bits
Graphics card: AMD Radeon Pro 5500M OpenGL Engine ATI Technologies Inc. 4.1 ATI-3.9.15
Broken: version: 2.91.0 Alpha, branch: master, commit date: 2020-08-25 19:28, hash: rB396d39c6b904
Short description of error
I consistently get a segmentation fault when adding a material slot to the plate in the attached file while in cycles rendered view (but not in any other viewport mode or in eevee).
Exact steps for others to reproduce the error
Open attached blend file in Blender with factory settings
Switch to rendered view
Select the plate
Click plus button in material properties to add a material slot
The plate turns transparent for a fraction of a second and then Blender crashes with a segmentation fault.