Same with my Ysolda. She walks backwards/shuffles like a penguin after the ransom quest. I also had to reload the quest three times in order for it to work correctly.
Ysolda did leave her cell, once even after just reading the note as the quest was suddenly "resolved" and I was still at home, but I had to nudge her home in the end; she did walk home (albeit backwards) but also shuffled weirdly whilst stuck in the middle of the road.
Only happened after this quest, pretty bummed about it
