Undo and ConstructionScript break the AttachChildren array

Undo fills AttachChildren array with null by the undo serializer.
After that, a construction script tries to remove child components from parent component's AttachChildren but it can't find its pointer.

To apply NonTransactional option in the UPROPERTY on the AttachChildren fixes this issue.

// USceneComponent
	/** List of child SceneComponents that are attached to us. */
	UPROPERTY(ReplicatedUsing = OnRep_AttachChildren, Transient, NoTransactional/*Added*/)
	TArray<USceneComponent*> AttachChildren;

1. Open attached project with UE4.22.
2. Select the right actor named CPP_Constructor in the level
3. Set "Num of Meshes" 20 in detail pane.
4. Undo
5. See log and find NumAttachedChildren has Incorrect number of element

-------------------------------------------------------------------

LogTemp: NumChildren:20 NumStaticMeshes:20
Cmd: TRANSACTION UNDO
LogEditorTransaction: Undo Edit Num Of Meshes
LogTemp: NumChildren:20 NumStaticMeshes:10

-------------------------------------------------------------------

The following screenshot displays the broken array.

[Image Removed]

[Link Removed]