How to reproduce:

1. Create new 2D Core project
2. In Hierarchy create new object (2D Object > Sprites > Square)
3. Select created object and in top menu open Window > Animation > Animation
4. In Animation window click Create (and save animation)
5. In top menu open Window > Animation > Animator
6. Dock Animator in visible place
7. Click Play button to enter Play Mode
8. Check console for errors

Expected results: No errors in console.
Actual results: Errors are thrown in the Console window
{noformat}
Removing null node
UnityEditor.Graphs.Graph:OnEnable ()
{noformat}
 

Reproducible on: 2022.2.0a10, 2022.2.0a19
Not reproducible on: 2022.2.0a9

Notes: Tested on Win11