Steps to reproduce:

1. Open the attached project
2. Open and play 'Game' scene
3. Notice everything works fine
4. Go to [PROJECT_PATH]/Assets/Data/Chars/Skeleton/ directory in the file explorer
5. Open one of the .anim files in any text editor
6. Find first "Path" variable and change it to anything other (e.g. Model/)
7. Focus the editor, either play the scene or try to re-open it - Unity Editor will crash

Note: After that the editor opens the scene as expected with the changed asset