When a Leaf group is added in Tree with a modified position then on dragging and dropping Leaf Group into Branch Group, Editor throws NullReferenceException refer the attached stack trace and video

Steps to repro:
1. Create a new Project.
2. Hierarchy > GameObject > 3D > Tree.
3. In Inspector > Tree > Add Leaf Group
4. Move Leaf Group concerning its position
5. Drag and Drop Leaf Group into Branch Group.

Actual Result:
NullReferenceException errors in the console.

Expected Result:
No errors in the console.

Workaround:
Drag and Drop unmodified Leaf Group into Branch Group.

Reproducible in:
2020.2.0a18, 2020.1.0b16, 2019.4.3f1, 2018.4.15f1

Environment:
Windows10 and macOS 10.15