Scene goes black because occlusion culling culls point light incorrectly. This happens in both editor (Windows and Mac) and player (tested on Windows Standalone).

1. Open scene OcclusionCullingBug.
2. Focus scene on Camera (eye)
3. Open and focus Occlusion window.
4. In Occlusion Culling Scene View overlay settings, make sure dropdown is set to Visualize.
5. In Occlusion Culling Scene View overlay settings, enable and disable the checkbox "Occlusion culling".
6. Notice that scene is mostly black (no light) when Oclusion culling checkbox is enabled even though neither camera or light is inside wall, nor are they occluded from each other.

This is a ship-stopper for the game. Very disturbing that the world sometimes turns completely black.