Collision boxes always have Navigation Area Class reset to NavArea_Obstacle on project load

Every time when reopening the project, Nav Area Class on collision geometry gets reset to "NavArea_Obstacle", instead of maintaining its state.

1. Create a Blueprint project using the empty template in 4.26.0
2. Add a Nav Mesh Bounds Volume to the default Level
3. Create a Blueprint based off an Actor and add a Collision Box to it
4. Make sure the Area Class is set to None
5. Save and close the Project
6. Reopen the project

Results: Nav Area Class is reset to "NavArea_Obstacle" from "None" 

Expected: Nav Area Class is still "None"