Creating a new Lightmap Parameters on a Gameobject from its Mesh Renderer component causes editor to throw NullReferenceException in the console refer attached video

Steps to Repro:
1. Create a new Project
2. Hierarchy > 3D object > Cube > Inspector > Lighting > Check Contrbute Global Illumination.
3. Lightmapping > Lightmap parameters > create new.

Actual Result:
Error is thrown in console

Expected Result:
No error in console.

Reproducible in:
2020.2.0a18, 2020.2.0a4

Working Fine in:
2020.2.0a3, 2020.2.0b16, 2019.4.4f1

Environment:
Occurring on Windows 10 & Mac 10.15.