I’m sorry for reanimating this thread. I’m having the same issue from time to time and I found some steps to reproduce it.
I have a Master Blueprint, child classes of this Master blueprint and some actors that use some of these child classes as child actors.
When in the Master Blurprint I change a value and then go ctrl Z for undo and recompile the master blueprint the child actors duplicate and become orphans. Really bad is it when I “draw” a value slider and undo it because then I have a lot of duplicates.
I hope this help to reproduce and fix this issue.