How to reproduce:
Open the attached project "Material 2022 2 8f1.zip"
Expected results: The thumbnail of "New Material.mat" in the Project window is grey
Actual results: The thumbnail of "New Material.mat" in the Project window is black
Reproducible with: 2021.3.18f1, 2021.3.20f1, 2022.2.10f1, 2023.1.0b7, 2023.2.0a5
Not reproducible with: 2020.3.46f1, 2021.3.17f1
Reproducible on: Windows 10
Note: Also reproducible with Prefab Previews (Prefab Previews are darkened / show the material on it as black, no details are visible)