I've experienced a fairly rare bug, but without any warning messages, my prisoners will occasionally revert their name to what it was before I renamed them, lose their restraints, and act like an invader in a raid. To clarify, they are no longer my prisoner and just break down the door and walk off without any sort of warning. They will often attack other prisoners, and must be downed before they can be recaptured. The option for "try to arrest" is not available.