When the child of an actor with the UCLASS specifier NotPlaceable has the UCLASS specifier Placeable it still isn't placeable. This behavior doesn't occur in 4.20.3.
Found in 4.22 CL#7053642
Reproduced in 4.24 CL#7273411, 4.21 CL#4753647
1. Create a clean project.
2. Create a new C++ ParentActor class based on AActor and use the 'NotPlaceable' specifier in UCLASS.
3. Create a new C++ ChildActor class based on ParentActor and use the 'Placeable' specifier in UCLASS.
4. Compile and try to place a ChildActor into a level.
Result: An instance of ChildActor cannot be placed in a level.
Expected: An instance of ChildActor can be placed in a level.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-77205 in the post.