*Steps to reproduce:*
# Open the attached project
# Open TestAnim Animation Controller
# Create a new Layer
# Switch to the Parameters tab
# Perform the Undo action

*Actual results:* "MissingReferenceException: The object of type 'UnityEditor.Animations.AnimatorStateMachine' has been destroyed but you are still trying to access it." error is spammed in the console after performing the Undo action

*Expected results:* No warnings or errors are thrown after performing an Undo action

*Reproducible with versions:* 2022.3.61f1, 6000.0.48f1, 6000.1.1f1, 6000.2.0a10

*Tested on (OS):* macOS 15.4.1

*Notes:*
* If Undo is performed while in the Layers tab, the issue does not occur