I share the experience. I’ve never had a problem getting all the actors in the the volume, the dilemma comes when moving all the actors out. It always leaves a ghost.
There doesn’t seem to be a way to clear the null array. I’m able to clear the overlappingActors array, but that doesn’t help me solve anything. The error is really complex. even after attempting to manually track entering and exiting actors, it will hiccup and miscount after a few movements.