When you take a thrall with the string and you use a teleport, the thrall was bugged, you cant see the corpse, you cant repair the string becouse you could lose the slave.
Please provide a step-by-step process of how the bug can be reproduced. The more details you provide us with the easier it will be for us to find and fix the bug:
Just so you know , Teleporting with a Ko’d thrall is not an intended behaviour (normally you shouldn’t be able to teleport with a roped thrall , at least in the devs set of mind , because we could by the past doesn’t mean it is what they wanted for the game )