Problem with round times in league tournaments

I have a league tournament with 4 teams opponents. When tournament starts it set 3 rounds: 6:00, 6:15 and 6:30. The first match takes place 6:05 and they submit/accepted score at 6:10. Then, I’ve checked that one of this teams can play the second round and submit his score before the time schedule for the second round (6:15). How can it be possible? And furthermore, I’ve checked a team can play the third round before the second… I think this couldn’t be possible.