How to reproduce:
1. Open the attached project "1241239.zip"
2. Open the "Test" Scene
3. Enter the PlayMode
4. Exit the PlayMode

Expected result: the grey cube is displayed in Scene and Game windows
Actual result: Scene window is grey and the Game window is completely black

Reproducible with: 2019.3.13f1 (URP version: 7.3.1)
Not reproducible with: 2019.3.0f1 (URP version: 7.1.6, 7.1.5), 2020.1.0b9 (URP version: 8.0.1, 8.1.0), 2020.2.0a11 (URP version: 7.1.8, 8.1.0)
Could not test with: 2018.4.22f1 - errors in a console when downgrading the project

Note:
- Updating XR Plugin Management package (from 3.2.9 to 3.2.10 or from 3.2.10 to 3.2.9) returns Scene and Game windows to the normal state until the PlayMode is entered again
- Deleting Tools > XR folder, Samples > XR Management folder and restarting Unity solves the issue