Continuity mistake: In the very last scene in New Zealand when Jordan is giving a motivational speech, he approaches his first target in the audience and says 'Sell me this pen.' As he does so, he holds out a pen in his right hand. When we cut to the shot to the person's face, we see that the pen is in Jordan's left hand; this goes on and on with every person. (02:52:10)
Continuity mistake: The glass of beer Donnie knocks over at the party (which falls onto the ground floor) is at its previous place in the next shot. (00:51:15)
Continuity mistake: When Jordan is inside his Mercedes trying to escape with his daughter, his wife breaks the door glass and the shot changes abruptly. When she breaks the windows Jordan doesn't have a ring, but when the shot changes the ring appears on his finger again. (02:43:30)
Continuity mistake: The yacht Jordan presents Naomi as a wedding present is different from the the one sailing in the next shot. The first one is bigger and has a different number of windows on the hull side. (01:10:35 - 01:11:15)
Continuity mistake: When the FBI is on the boat and Jordan introduces the two models, his hand is either behind the back of one of hers or loose, depending on the angle. (01:29:40)
Continuity mistake: Just before Jordan saves Donnie for his choking he gets a shot of cocaine which disappears from his nose and mouth few shots later. (02:06:15 - 02:06:45)
Continuity mistake: On the yacht Jordan offers some food to Patrick Denham and the other FBI agent. Patrick stands, while the other walks towards the table. In the next shot he is again behind agent Patrick Denham. (01:29:50)
Continuity mistake: After Steve Madden talks to the office, Jordan talks in the face of two employees. When talking to the second one, the hand holding the microphone and the hand around the employee's neck swap. (01:22:40)
Continuity mistake: When Jordan goes to lunch with Mark, Mark is wiping his nose with a napkin as the waiter talks to him in the wide shot. As the waiter says the next word, they cut to a close-up of Mark, but the hand is missing the napkin and is in a completely different position reaching into his suit pocket. (00:08:25)
Continuity mistake: After Jordan and Naomi make love for the last time, his pants suddenly appear on him when he's about to leave the bed. (02:40:20)
Chosen answer: As seen from Donne's reaction when the FBI storm the building shortly after, It should be assumed that Donnie told the FBI himself, and kept the note as evidence. One of the reasons for this could be that Donnie must have felt betrayed or something similar.
Dra9onBorn117