How to reproduce:
1. Open the attached project
2. Go to the Project window -> Models -> select Person2.fbx
3. Go to the Inspector window -> Rig -> Set Animation Type to any other type from Humanoid and press apply
4. Set the Animation Type back to Humanoid and press apply (crash occurs)

Expected: Rig setting are successfully applied when the Animation Type is set to Humanoid
Actual: Editor crashes when setting Rig Animation Type to Humanoid

Note: Open the project again and make some changes in the Rig settings while the Animation Type is Humanoid and press apply (crash occurs)