So I am the Duke of Irombro. I have a knight of Irombro city under me. I was looking at the Govern regions button for a week or two to try and appoint him to one of the regions under my Duchy, but I couldnt. Only nobles available were knights that already had an estate there or nobles without an estate. So I tried kicking him out of his estate, and only then I was able to appoint him as lord.
Working as intended?
IIRC, weren't Dukes allowed to appoint all the nobles under their Duchy to regions under their Duchy?