It’s probably not 1 as the admin can force-start games before they are full. The places are auto-filled with AI’s named “Automation”. 2 is very possible.
The above screenshot shows he was the 22, 23 or 24th person to join. If he was the last person to join, he may have immediately quite because he felt the starting position was unfavourable. Maybe there should be a grace period before the game starts to allow the last player to quit if they change their mind about joining. Maybe 2-3 hours. During that time anyone can quit and the game will go back to waiting for players to join.
Another option for turn-based games only is to wait until everyone has committed their turn before starting. That is, the game will start as normal and count down to first turn-deadline. After reaching the deadline it will kick everyone who did not commit and go back to waiting for players.