When testing with a simple setup, as follows:
MySceneComponent has a UProperty(VisibleAnywhere, BlueprintReadOnly) of a USphereComponent pointer, initiated in the Constructor
AMyActor has a UProperty(VisibleAnywhere, BlueprintReadOnly) of a UMySceneComponent pointer, initiated in the Constructor
With this setup, creating a Blueprint of MyActor results in a hierarchy where the USphereComponent is shown as the parent of the UMySceneComponent. Clicking on the USphereComponent shows an empty details panel. Clicking on the UMySceneComponent is shows duplicates for multiple details panel entries.
Adding an instance of AMyActor directly to the level does not show the hierarchy issue, and the USphereComponent displays its details as expected.
Note: Adding a "SetupAttachment" call to the Constructor of MySceneComponent to attach the USphereComponent pointer to it fixes the hierarchy issue, but not fix the details issue.
Edit: There are also inconsistent results with these components when adding them to the blueprint directly, such as the USphereComponent vanishing entirely from the hierarchy and the details panel having certain fields missing such as Collision Presets.
There's no existing public thread on this issue, so head over toAnswerHub just mention UE-70267 in the post.