In the French cooking school the master chef demonstrates an exaggerated wrist motion necessary for cracking an egg, but when he cracks the egg his wrist is stiff and his arm moves from the shoulder. He makes this mistake twice.
In the boardroom scene at the end, when Linus is standing in front of the window, Harborside Terminal in Jersey City is visible. Once he leaves the room, this very large building disappears from the background.
Near the beginning of the film, when Linus is explaining his plastic to David, he holds a lighter to the piece of plastic and brags that it cannot scorch. However, as he turns the plastic over, a giant black spot is visible where the plastic was scorched. In the next shot, the spot on presumably the same piece of plastic has disappeared.
(At about 14:00) While Sabrina is writing her suicide note to Father, we see her hand from two perspectives. From the side, we see Sabrina writing with two fingers on the pen (first and second fingers). From above we see only one finger on the pen (first finger).
After Sabrina tells Fairchild that the moon is reaching for her, we see a shot of the moon through the trees at the Larrabee party. Directly above and to the right of the moon, you can see the strings and holes of that backdrop.