Steps to reproduce:

1. select a game object and right click 
2. select create empty parent
3. undo

Actual results: InvalidOperationException is thrown

InvalidOperationException: HierarchyNode(2239:1) not found

Unity.Hierarchy.HierarchyViewModel.GetParent (Unity.Hierarchy.HierarchyNode& node) (at <96f92eb7250f45b4bffe77e0b7f03906>:0)

Unity.Hierarchy.HierarchyView.ExpandParents (System.ReadOnlySpan`1[T] nodes) (at ///unity/Modules/Hierarchy/Managed/HierarchyView.cs:1424)

Unity.Hierarchy.HierarchyView.Frame (System.ReadOnlySpan`1[T] nodes) (at ///unity/Modules/Hierarchy/Managed/HierarchyView.cs:998)

Unity.Hierarchy.Editor.HierarchyGlobalSelectionHandler.SyncViewModelFromGlobalSelection (System.Boolean frameSelection) (at ///unity/Modules/HierarchyEditor/Managed/HierarchyGlobalSelectionHandler.cs:57)

Unity.Hierarchy.Editor.HierarchyGlobalSelectionHandler.<OnGlobalSelectionChanged>b__8_0 () (at ///unity/Modules/HierarchyEditor/Managed/HierarchyGlobalSelectionHandler.cs:129)

Unity.Hierarchy.HierarchyView.<DoUpdate>g__ExecuteActions|190_3 (Unity.Hierarchy.CircularBuffer`1[T] actions) (at ///unity/Modules/Hierarchy/Managed/HierarchyView.cs:1845)

UnityEngine.Debug:LogException(Exception)

Unity.Hierarchy.HierarchyView:<DoUpdate>g__ExecuteActions|190_3(CircularBuffer`1) (at ///unity/Modules/Hierarchy/Managed/HierarchyView.cs:1849)

Unity.Hierarchy.HierarchyView:<DoUpdate>g__DoUpdateStage|190_4(UpdateMode, Double) (at ///unity/Modules/Hierarchy/Managed/HierarchyView.cs:1877)

Unity.Hierarchy.HierarchyView:DoUpdate(UpdateMode, Double) (at ///unity/Modules/Hierarchy/Managed/HierarchyView.cs:1892)

Unity.Hierarchy.HierarchyView:UpdateIncrementalTimed(Double) (at ///unity/Modules/Hierarchy/Managed/HierarchyView.cs:501)

Unity.Hierarchy.Editor.HierarchyWindow:Update() (at ///unity/Modules/HierarchyEditor/Managed/HierarchyWindow.cs:1014)

UnityEditor.EditorApplication:Internal_CallUpdateFunctions() (at ///unity/Editor/Mono/EditorApplication.cs:404)

Reproducible with versions: 6000.5.0a7    

Not reproducible with versions: 6000.5.0a6

Can’t test with versions: 

Tested on (OS): macOS

Notes: