How to reproduce:
# Create new project
# Create any GameObject in Hierarchy window
# Open Windows > Animation > Animation
# Create New Animation and Save
# Open Windows > Animation > Animator (important)
# Drag/Drop new Animation into Animator Controller window
# Right click on Any State Node
# Make transition to the added Animation
# Click on the Transition Arrow
# Observe the error in the Console window

Expected results: No errors
Actual results: Multiple errors are thrown in the Console window
{noformat}
NullReferenceException: Object reference not set to an instance of an object
UnityEditor.Graphs.AnimationStateMachine.AnimatorStateTransitionInspector.DoErrorAndWarning () (at <b33671bcae5847dba5182ede845a38ef>:0)
UnityEditor.Graphs.AnimationStateMachine.AnimatorTransitionInspectorBase.OnInspectorGUI () (at <b33671bcae5847dba5182ede845a38ef>:0)
UnityEditor.UIElements.InspectorElement+<>c__DisplayClass71_0.<CreateIMGUIInspectorFromEditor>b__0 () (at <808fed1db5d34c2a9416f9a4a396d0d5>:0)
UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr, Boolean&){noformat}
 

Reproducible on: 2022.1.0a6, 2022.1.8f1, 2022.2.0a18, 2023.1.0a2
Not reproducible on: 2022.1.0a5

Notes:
- Tested on : Win11, MacOS Silicon (Monterey 12.3.1)
- Moving mouse cursor around in the Inspector window throws more errors.