Reproduction steps:
1. Open the user's attached project "2021.2 Beta.zip"
2. Go to Assets > "bug.scene"
3. In the Hierarchy window select a game object named "111"
4. In the Inspector window select "Edit Graph"
5. Right-click on the "Start" graph and choose "Open in new window"
6. Select "111" in the top toolbar of the new Script Graph window to return into the State Graph

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

Reproducible with: 1.7.2 (2020.3.20f1, 2021.1.24f1), 1.7.3 (2021.2.0b15, 2022.1.0a11)
Not Reproducible with: 1.7.1 (2020.3.20f1, 2021.1.24f1, 2021.2.0b15, 2022.1.0a11)
Could not test with: 1.4.15 (2019.4.31f1)(Bolt errors)