On opening Terrain Assets in the "Prefab Editor", then it causes the editor to throw NullReferenceException, refer the attached video

Steps to Repro:
1. Open an attached or create a new project
2. Hierarchy > Create > 3D Object > Terrain
3. Drag and Drop Terrain in the project window to create a prefab
4. Select the prefab and click "Open Prefab" button

Actual Result:
1. NullReferenceException is thrown on opening Terrain Assets in Prefab Editor
2. The error occurs first time only

Expected Result:
Terrain Assets open in the Prefab Editor without throwing any exception

Occurring on:
2020.2.0a13

Working fine on:
2020.2.0a12, 2020.1.0b11

Environment:
Occurs only on Windows 10