Steps to reproduce
1. Download and open attached project.
2. Open ‘t1’ scene.
3. Turn off auto-mode and bake the scene.
4. Manually clear GI cache (on Mac it’s in Library/Caches folder; on Windows - AppData\Local\Unity\Caches).
5. Clear baked data (from Lightmap window).
6. Save ‘t1’ scene and load ‘t2’ scene.
7. Reload ‘t1’ scene.
8. Bake it again - observe that the baking pipeline is stalled and lots of errors appear.

Expected behavior
After switching to scene t1, the lighting should bake without any problems.

Actual behavior
The baking pipeline stall, and the lighting never gets baked.

Notes
Tested and confirmed that the issue occurs in these version of Unity:

• MacOS: 2018.2.0a1, 2018.1.0b7, 2017.3.1p1, 2017.1.3p7, 5.6.5p2
• Windows: 2018.1.0b6, 5.6.5p1