3 times with the same person? Yikes.. this is a much bigger red flag than getting hired in 24 hours. That tells me they are unsure of me or themselves getting an offer on the spot is a sign they actually need to fill the position and they believe you can
To me it just sounds like a small scale operation and the manager is being careful which is great.
Perhaps what happened after the first two meetings, the manager sat down and analyzed his list of reasons he's excited about the candidate as well as any potential concerns that he saw.
The subsequent rounds may have in part been structured to dig into the areas of concerns to assure themselves they aren't real issues or can be lived with.
This wouldn't scale at a FAANG but for a smaller shop it's probably close to optimal.
