Certain betting systems may show matches for games that end up "falling out" of the system by the time the game starts. There may also be games that enter the system that were not previously showing.
This is because many systems use parameters that involve fluctuating numbers (betting percentages, spread ranges) that change throughout the day.
For example, the system above (Contrarian Unders for Winning Teams) requires there to be between 8% and 35% of bets on the over. If the percent of bets on the over moved to 36% for the Red Sox-Rays game, it would "fall out" of this system.