It shows that she's missing work and her job performance drops but she just won't follow through on the action. I had her quit her job (at level 5 or 6) and get rehired (at level 3), but the same thing happened. I tried making her go to the building on her own and then told her to go in and work, but it just dropped out of her queue like before. She gets the action in her queue about catching her carpool, but then it just drops from her queue.
My sim got pregnant with triplets and then wouldn't go back to work after her maternity leave.
I've recently had this same problem with the science career.
