I accepted an offer, went through a day of training and a half day of work, then left at lunch. Had to use the office phone because this was before I had a cell phone. Turns out I couldn't physically handle working in a tire factory. I was itchy and sweaty and miserable.

Figured out years later I was allergic to latex.

What I'm saying is, maybe the company wasn't a good fit and the candidate didn't figure it out until after onboarding.