Well try to understand garbage collection first : see here
and
Actors and their Components are frequently an exception to this, since the Actors are usually referenced by an Object that links back to the root set, such as the Level to which they belong, and the Actor’s Components are referenced by the Actor itself. Actors can be explicitly marked for destruction by calling their Destroy function, which is the standard way to remove an Actor from an in-progress game. Components can be destroyed explicitly with the DestroyComponent function, but they are usually destroyed when their owning Actor is removed from the game.
IE: something might not be getting deleted correctly. or in the correct order.