Slave on decay base with wrong name or function

[Kapoteeni]

If memory serves correctly, there was a database error that caused another thrall (a T4 tanner) to spawn with the wrong name, in this case Donia.

Slave with wrong name or function

There was a database error that caused certain NPCs to spawn with the wrong name. Donia was one of the names that were applied to a wrong thrall. The one you found (the tanner version) is one of these thralls. It’s supposed to be someone else (a T4 tanner), but Donia’s name tag seems to be stuck on him/her.

So the tanner you found simply has the wrong name.