NB: I'm not sure if this is actually a bug, or if I just don't know enough about what constitutes a new user. It just seems off to me.
The first post in question: https://stackoverflow.com/review/first-posts/1376311
In the context of reviews, is a new user just someone who has never posted an answer no matter their age or rep?
Also: How is it possible for a user to have -1 other answers? Could this be related?