At the beginning, one of the two IMF operatives in Miami puts on the "death mask" Casey has created to make Van Cleve (Ed Nelson) think he has the power of precognition. The man is wearing the mask when Cleve sees him on the sidewalk; then as he stumbles into traffic and is "hit" by the van he is no longer wearing the mask; then after the van "hits" him he suddenly is wearing it again and quickly tears it off.
When Casey is shuffling cards on the airplane, the close-up shot of her hands shows she has a ring on the pinkie finger of her right hand, and she does not have long sleeves on under her jacket. When the shot shows her face, the ring is now on the ring finger of her right hand, and she has long sleeves on under her jacket.
When Jim is playing roulette, he places inside bets on 7, 12, 14, and 16. Willie spins the wheel and announces the winner as 12 red and even, and Jim reacts as though he has lost again. When Willie rakes in the chips, the bets on 12, 14, and 16 are no longer on the table and the bet on 7 has changed into a corner bet on 4,5,7,8.
The photo of Royce that Phelps looks at while listening to the taped recording is a picture taken of him from the first scene when Royce has his confrontation with Van Cleve. There would be no way Phelps could have such a photo.
When Van Cleve looks in Casey's bag full of money the camera goes in too close and you can read that it is movie money and not legal tender.