How to reproduce:
1. Open the attached “IN-114253_Tutorialcase_Toolkit_Creator_3d.zip” project
2. Open the “SampleScene”
3. Choose the “Cylinder” object in the Hierarchy
4. In the Inspector, under the “Cylinder” script component, change the “GameObject” field to “None”
5. Observe the crash

Reproducible with: 2021.3.45f1, 2023.1.0a1, 6000.0.59f1, 6000.2.7f1, 6000.3.0b4, 6000.4.0a1

Reproducible on: Windows 11
Not reproducible on: No other environments tested

Workaround:
1. Create a public GameObject field in the Cylinder script with a different name other than “m_GameObject”
2. Change the Binding Path for “#propGameObject” in the UI builder to the name of newly created field

First few lines of the stack trace:
0x00007FFBA97618C7 (Unity) GetElementMapKey
0x00007FFBA976374B (Unity) ActiveEditorTracker::PopulateSubVector
0x00007FFBA976A06A (Unity) ActiveEditorTracker::UpdateSubObjectsVector
0x00007FFBA975F31A (Unity) ActiveEditorTracker::DidFlushDirty
0x00007FFBA97605D1 (Unity) SceneTracker::FlushDirty