Something like that happened with a team at my previous employer. The person nailed the interview, but when the person started they seemed pretty clueless about

Something like that happened with a team at my previous employer. The person nailed the interview, but when the person started they seemed pretty clueless about the position, the programming languages, and the tools that the team used. Plus the person's personality seemed a little different. The company quickly figured out that a front did the interview of this person, and that they were hired under false pretenses. Immediate dismissal. This sort of situation seems to have become very common in the last couple or three years.