Unity Editor crashes when saving/closing the imported "The Courtyard" project

1. What happened

Unity Editor crashed (reliably reproducible) when saving "The Courtyard" project, imported from the Asset Store.

2. How we can reproduce it using the example you attached

- Download and import "The Courtyard" project from the Asset Store;
- Open the Scenes/Courtyard Scene;
- Save the Scene;
- Observe the Editor crashing and the bug reporter opening.

Note: The crash also happens when quitting the editor while the project is open or switching to a different project.

Regression: Tested on 5.4.0b13, 5.4.0b8, same behavior.