Depends on map and players/civs. If you and your friends are high 1v1, but play just a few TG from time to time, it’s possible that you are more skilled than your opponents, for example, so a 3v4 is possible even after 15 minutes.
Now that I kindly pointed it out to you, you could read again to see how it’s not a matchmaking problem.
It’s possible also that your team gamble an all-in and emerge victorious. A drop or rage quit doesnt mean, necessarily, end game for a team.