Steps to reproduce:
1. Open new project
2. Add ArticulationBody component to a new GameObject
3. Add another ArticulationBody component to a child GameObject of the GameObject in Step 2
4. Change the Anchor position on Articulation Body on the GameObject from step 3
5. Try to Undo your change (Cmd+Z or Ctrl+Z)
6. The Anchor position change has not been undone

Expected: Most if not all properties in the Articulation Body inspector should be undoable
Actual: Some of the properties can be undone and some can not

Reproduced:
Version: 2021.2.0a10.1481
Revision: trunk f4de2e18f414
Built: Mon, 15 Mar 2021 00:58:40 GMT

2021.1.0f1, 2020.3.1f1, 2020.2.7f1, 2020.1.17f1.4949