Continuity mistake: When Nathan and Tom are on the rooftop talking, Nathan gets up to leave and Tom is facing to his left. Camera angle changes to a wide view and he's looking at Nathan but when the camera angle changes to a closer view he is once again looking to his left. Happens about 3 times during the entire scene.
Continuity mistake: In the scene where Redford asks his secretary to hide Pitt's file, justifying his paranoia with a Noah reference, he puts on his jacket and walks toward the door, leaving the collar slightly upturned. The camera goes to her and then back to him, but when it returns, his collar is perfect.