NullReferenceException when selecting a transition from Any State in the Animator window

How to reproduce:

1. Open the attached project "AnimStateIssue.zip"
2. Open Assets/Scenes/SampleScene.unity
3. Select "char_1" in the Hierarchy window
4. Open the Animator window (Window>Animation>Animator)
5. Select the "AnyState->RifleIdle" transition

Expected results: No errors thrown in the Console window
Actual results: "NullReferenceException: Object reference not set to an instance of an object" thrown in the Console window

Reproducible with: 2022.1.23f1, 2022.2.0f1, 2023.1.0a7
Not reproducible with: 2023.1.0a8, 2023.1.0a23
Could not test with: 2020.3.42f1 (C# 9.0 not supported), 2021.3.15f1 (compilation errors in the Console window)

Reproducible on: Windows 10