How to reproduce:
1. Open the attached “IN-89462_TestOptimisation” project
2. Open “SampleScene”
3. Make sure the Project Settings tab is docked in the Editor
4. Open Project Settings > Graphics and set Lightmap Modes and Fog Modes to “Custom”
5. Open Game view and make sure Project Settings tab content is not visible
6. Enter and exit Play mode
7. Observe Project Settings window where Lightmap Modes and Fog Modes do not display the Custom options

Expected result: Lightmap Modes and Fog Modes display their Custom options
Actual result: Lightmap Modes and Fog Modes do not display their Custom options

Reproducible with: 2023.3.0b7, 6000.0.32f1, 6000.1.0a9, 7000.0.0a14
Not reproducible with: 2021.3.47f1, 2022.3.55f1, 2023.1.0a21
Couldn't test with: 2023.1.0a22, 2023.3.0b6 (another bug introduced preventing reproduction)

Reproducible on: macOS 15.1.1 (M1 Max), Windows 11 (by user)
Not reproducible on: No other environments tested

Workaround: If the Project Settings tab is open in the Editor (e.g. dock instead of Inspector) while entering and exiting Play mode it does not reproduce

Note: Issue is caused by Project Settings > Editor > Enter Play Mode Settings > When entering Play mode : “Reload Scene only” or “Do not reload Domain or Scene” settings.

Note that you can repro the issues with any project. No need for the original customer project (since I had difficulty to import this project in u7 it is good to know we can use any project).