re-indoctrination of hatched followers

hi, i tried to use the reindoctrination function to change the appearance of a hatched follower right when they reached adulthood and it almost seems like i’m just not allowed to do that? all i can do is change the name and the rest is greyed out. i just wanted confirmation that this wasn’t a glitch and that i’m just not allowed to do it, as the switch version of COTL is glitchy and i couldn’t find anyone else answering or asking this question.

edit: i was also wondering if their appearance is revolved around their parents, as the two i hatched look almost identical just different colors. unless there’s some kind of stage in life where i’m not allowed to change them for a few days? idk lol.