Reproduction steps:
1. Open the attached project
2. Open "Lit Scene" Scene in the Assets folder of the Project window
3. Enter Play Mode
4. Observe the lighting of the Scene
5. Open "Unlit Scene" Scene in the Assets folder of the Project window
6. Enter Play Mode and wait 2 seconds
7. Observe the lighting of the Scene
Expected result: the Skybox lighting should be identical to the "Lit Scene" Scene when the Scene was played directly
Actual result: there's no Skybox lighting
Reproducible with: 2019.4.38f1, 2020.3.33f1, 2021.3.1f1, 2022.1.0f1, 2022.2.0a12
Workaround is to enable Auto Generate checkbox in the Lighting window on the "Lit Scene".
Notes: the "Unlit Scene" Scene has no "Lighting Settings Asset" assigned, thus the "Auto Generate" option on the "Lighting.lighting" Asset has no effect