Steps to repro:
1. Open the attached project 'case_886275-Progressive_Lightmapper_Adventure_Game' and 'ProgressiveLightmappingExample' scene;
2. In the Lighting window select Clear Baked Data;
3. In the Lighting window set Lightmapper to Progressive CPU;
4. In the Lighting window press Generate Lighting button;
5. Wait until the Lighting is baked;
6. In the Lighting window change Lightmapper to Progressive GPU;
7. In the Lighting window press Generate Lighting button;
8. Wait until the Lighting is baked;
9. In the context menu select File>New Scene;
10. If the prompt menu appears, click Save;
11. When the new scene is opened in the Lighting window press Generate Lighting button.

Actual result:
Editor crashes. See attached video.
The stacktrace is empty.
Regression introduced in Version 2020.1.0.

Expected result:
Editor doesn't crash.

Notes:
- Reproducible in 2020.2.0a10, 2020.1.0b7;
- Not reproducible in 2019.3.13f1;
- Reproducible on Windows with GeForce RTX 2080 GPU;
- Could not test on OSX, because the OS Kernel panic happens when trying to bake this repro project (known issue);
- Not reproducible in the URP sample scene, seems to be specific to the project;
- In Version 2020.1 the crash happens after opening the newly created scene as opposed to 2020.2, where it happens after baking the lighting of the newly created scene;
- The crash happens regardless on whether the Disable cookie support checkbox is enabled or disabled in the Project Settings;
- The crash is reproducible in 2020.1 almost in 100% of cases, while in 2020.2 it's reproducible much less often (preferrably in the Rebel Racing project, please use it as a repro in 2020.2).

- The crash might not repro everytime. If it doesn't happen try following additional steps:
12. Open 'ProgressiveLightmappingExample' scene;
13. Bake it with GPU Lightmapper;
14. Open the new scene via the context menu;
15. In the Lighting window press Generate Lighting button;

or

- Restart the Editor and repeat all the steps again (this seems to have the effect on the repro sometimes).