Changing root component in C++ does not apply correctly to map placed actor instances

Edit: Please investigate for not only root component changes, but native component hierarchy changes in general and whether those hierarchy changes apply to actor instances saved as part of maps.

Original:
When introducing a different root component in C++, map placed actor instances that were already saved do not have a correct component hierarchy. The repro steps describe a simple scenario where a new root component is introduced above the previous one.

I attached a repro project in which a map was saved with an already placed actor, and afterward the C++ constructor was updated to introduce a new root component. The map placed actors don't have a correct hierarchy, while new ones do.

Also see related UDN of user reporting the problem.

I attached a project in which the repro steps have been completed up to the last steps. I recommend starting from that project.

Steps to repro in UE 5.1.0+:

• Create a C++ actor class AReproBaseActor that defines no root component
• Create a C++ subclass of it, AReproStaticMeshActor that creates a StaticMeshComponent as root component
• Create a BP of AReproStaticMeshActor, BP_ReproStaticMeshActor, that sets the mesh comp's static mesh to Cube
• Create a map Map1 and place a BP_ReproStaticMeshActor on it
• Modify the constructor of AReproBaseActor to create a USceneComponent and set it as root component
• Modify the constructor of AReproStaticMeshActor so the existing static mesh component uses the new scene component as parent
  In the attached project the steps have been followed up to here.
• Open the editor again, notice that the BP_ReproStaticMeshActor that's already placed has the scene component and static mesh component as siblings instead of the mesh comp attached under the scene comp.
• If you place a new BP_ReproStaticMeshActor, it does have the scene component as parent of the static mesh component

Expected:

• Even for the BP_ReproStaticMeshActor that's already placed, the scene component should be the parent of the static mesh component