Reproduction steps:
1. Open the attached project "ReproProj"
2. Open the “/Assets/Scenes/SampleScene.unity” Scene
3. In Hierarchy, click any “X Bot@Capoeira” Prefab
4. In Inspector, Right-click the Animator
5. Click Optimize Transform Hierarchy
6. Click Unpack and Optimize in popup
7. Undo changes (CTRL Z)
8. Redo changes (CTRL Y)
Expected result: Changes are redone, or if not possible a warning is shown
Actual result: Editor crashes
Reproducible with: 2021.3.31f1, 2022.1.0a11
Not reproducible with: 2022.3.11f1, 2023.1.16f1, 2023.2.0b13, 2023.3.0a9
Fixed in: 2022.1.0a12
Reproducible on: Windows 10 Enterprise 21H2
Not reproducible on: No other environment tested
First few lines of the Stacktrace:
0x00007ff6b99d7157 (Unity) StructureUndoBase::CollectTransformsRecursive
0x00007ff6b99de935 (Unity) StructureUndoBase::RestoreObjects
0x00007ff6b99d5394 (Unity) StructureUndoBase::ApplyInternal
0x00007ff6b99cdd17 (Unity) ObjectUndo::ApplyRedo
0x00007ff6b99dd277 (Unity) UndoManager::Redo