Spent an hour leaving and re-entering with no luck. I did capture a lot of people in the meantime; I'm not sure how it works, but maybe they "diluted" (for a lack of a better term) the pool of NPCs that can spawn?
The code shouldn’t let that happen, because it forces her to spawn if a quest needs her. The only reason she wouldn’t spawn is if you don’t have her in your pool of characters at all, and I have no idea how someone could get removed from that pool. So, that’s definitely weird.
I’m not quite sure what to do about it though.