Exceptions thrown and Inspector broken when saving project while prefab variant is selected

[Amanda End]

Unity Version: 2019.3.0f3

Odin Inspector Version: 2.1.8.0 (I believe? Whatever version downloads from Unity Asset Store as of 1/9/2020)

Repro Steps:

1. Open attached project
2. Select prefab named TestPrefab Variant (don’t open, just select so you can view in the inspector)

3. Change the TestString to a different value

   1. Notice here that the label doesn’t bold like it should when a variant overrides the parent, I believe this is another bug, but not the one I’m posting about.

4. Save the project (File > Save Project)

Expected Results: Should save without error

Actual Results: Repeating ArgumentNullException errors are thrown, inspector bugs out and doesn’t render components properly.

Notes: Error and Screenshots can be found with the Project files in the attached zip