Welcome to the forum!
Yes, NPC's that are added to the household will often lose their jobs. Gardeners, gym trainers, mixologists, and apparently university professors become unemployed when you move them in. There really isn't anything you can do about it. If you put that Sim in the education profession, she'll probably have to start at level 1.
What happens is that when you go to a community lot, the game picks up Sims to serve in various roles appropriate to that lot. Sims living in a house who have a regular job will be exempt, but unemployed Sims, and Sims not in a house, won't. When you make those Sims playable, they lose their "jobs."