Reproduction steps:
1. Open the attached “IN-96870.zip” project
2. Open the “GameScene” Scene
3. Open the Lighting Window (Window > Rendering > Lighting)
4. Click Generate Lighting
5. In the Scene view zoom closer into the shadows on the ground
6. Select “Sun” GameObject from the Hierarchy
7. Disable and enable the GameObject a few times to observe the difference

Expected result: The shadows remain the same both when the Light is enabled/disabled
Actual result: The shadow changes (is darker when Light is enabled)

Reproducible with: 2023.1.0a20, 6000.0.43f1, 6000.1.0b11, 6000.2.0a7
Not reproducible with: 2022.3.60f1, 2023.1.0a19

Reproducible on: Windows 11
Not reproducible on: No other environment tested

Notes:
- Does not reproduce when in Play mode (only baked shadow is cast), and after the Play mode is entered, the issue does not reproduce
- Closing and reopening the project also seems to fix the issue until lighting is generated again
- Does not reproduce for the same prefab when used not as a Terrain Tree