How to reproduce:
1. Open the attached "1370033.zip" project
2. Open the SampleScene scene in the "Scenes" folder
3. Open the "Prefabs" folder in the "Assets" folder

Expected result: Prefab previews are visible
Actual result: Prefab previews are invisible

Reproducible with: 8.1.0 (2020.2.0a18), 10.2.0 (2021.1.0a9), 12.1.0 (2021.2.0b17), 13.0.0 (2022.1.0a12)
Not reproducible: 7.7.1 (2019.4.32f1), 8.1.0 (2020.2.0a17), 10.6.0 (2020.3.21f1), 11.0.0 (2021.1.0a10, 2021.1.27f1)
Couldn't test: 2021.2.0b1, 2022.1.0a1 (Shader errors when creating the project) 2022.1.0a13 (No URP template)

Note:
- If somehow Prefab previews are visible modify them in any way then save
- After testing it would seem the issue is not with the package versions themselves