Steps to reproduce:

1. Open attached project
2. Open scene "Winterlandscape/main_scene"
3. Notice that it has OC baked
4. Open up "LoaderScene" scene and run it
5. Once "main_scene" is loaded select "Main Camera" from it and notice that Occlusion Culling cannot be visualized - occluded objects are still rendered

Workaround:
1) with Loader scene open, right click main_scene and select "Open scene additively". (or vice-versa)
2) Bake occlusion with both scenes open.

Reproduced with: 5.5.0b11, 5.5.0f2