In the opening sequence, both the narrator and the track announcer refer to the "fifth" race. But the bet tickets that Marvin Unger has say "sixth race". The subtitles say both 5th and 6th for different references.
During the robbery you clearly see that a significant amount of the money is in neatly banded bundles of brand new crisp bills yet when it is transferred from the dufflebag to the suitcase all of the money is loose, unstacked & well used.
When Nikki tries to drive away after shooting the horse, he supposedly sustains a flat tire from running over the horse shoe discarded by the parking attendant. The tire is already flat before he starts the car.
During the fight scene at the race track, where the robber is let in the door in two scenes told from from different angle, you clearly see that the door is open ed in different ways, and also that the robber is much quicker in the second time, though the scene is supposed to be the same.
On the day of the robbery a scene with the character, Johnny Clay, shows him awake and dressed and says "At seven that morning, Johnny Clay began what might be, the last day of his life". He wakes another character and they talk awhile. This scene is immediately followed by an airport scene in which the narrator says: "It was exactly 7:00AM when he got to the airport".
When Sherry is removing her makeup in their room, George is moving toward her. When he hits his mark, announcing that he is dropping out, the shadow of a crew member's head is clearly seen on his shirt and then fade on the right side.