So yeah, I ran into this bug with a slave. Only afterwards i found out about the bug fix mod, which solves the problem. But it doesn't seem to work retroactively. Is there any way to recover from this? I don't have a recent save before it, so that is not an option.

Thanks in advance.

The in-game fix would be the Oblivion Potion. Otherwise you would need to open the save file, locate the slave, and change either reset "consent" to false or clear "levelupreqs" to {}. An online JSON editor may help with the first option, not sure about the latter.

Thanks, I edited the save file. Was safer and quicker, than using these scary sounding potions.