Error on ItemId prop type check when a ModelVersion has no parent

1. In dev only, open the Models page under the user menu.
2. Open the dev tools.
3. Browse to any model that has some model versions with no parent version.

4. [Vue warn]: Invalid prop: type check failed for prop "itemId". Expected String with value "null", got Null  
     at <ItemId item-id=null > 
     ...

5. Cry.