It seems to be that 24 hours after a game is played it moves from the top line (current/next game) to the bottom line (last past game).
For non-Utopia leagues, this happens at the same time for all games, so there are always two full lists of games in each line. With the variety of game times in Utopia leagues, there is a a period where some games have already moved from the current/next line to the past line while others have not. When the first game moves, all of the prior past games are removed, and until all of the games move, the none of the next upcoming games are shown. So for the day after games, only those 8 games are displayed, split between the two lines.