Not sure what you mean, as yes, this is a bug they note they have now resolved. The bug presumably isn't that when you delete something on most any device that it's not actually deleted, but rather the bug is that something in their code allowed for a marked as deleted item (no longer accessible to the user), to become accessible to the user again without the user doing any data recovery services. While only Apple currently knows, but the most obvious answer would be that while they want to wait until enough users have applied the fix since perhaps even though incredible rare, it might be something a technical person could replicate on others devices if they know the bug. I would be very surprised if they don't eventually disclose it, but assume will be after it's no longer exploitable to the vast majority of people. All speculation of course.