Continuity mistake: In Dylan's first scene, he walks into a meeting room at the FBI and requests a minute with the director. During this, Dylan has a mug in his left hand and a file in his right hand. There is a long shot in this scene, with the shot several meters from Dylan, where the file is suddenly in his left hand. Then in the next shot of Dylan after that, the file is suddenly back. (00:07:20)
Other mistake: Merrit claims he has never ridden a motorcycle and talks about how unsafe it is, but is seen riding one in the first film.
Continuity mistake: Jack is shown wearing a security guard uniform throughout the entire infiltration of the launch party. When the party has been intercepted and Jack is exposed to everyone, he is still shown wearing the security guard uniform, but when the Horsemen are on the roof minutes later, Jack is suddenly back to wearing his leather jacket and T-shirt. Even if this is needed for the story and some time had passed between scenes for him to change, Jack was being chased by the FBI and was in a hurry to escape the building, so he would not have had anytime to change back, nor would he have risked wasting any time changing his clothes anyway.
Continuity mistake: When Walter is explaining to Daniel he was the voice he heard earlier in the movie, he mentions that he put his phone on a by-wave syphon pad, the scene flashes back to when Daniel was communicating with the voice and it is discovered there was a device planted inside the well, shown behind a grid. When Daniel visited this place earlier on in the movie, the grid inside the well was visible, but there was no sight of the device inside the grid. (00:06:05 - 01:11:00)
Continuity mistake: When Agent Cowan is asking the FBI director what happened, she says that they are gone and tells the man beside to come with her. She and the man then start walking, with the FBI director walking a couple of feet ahead of the man. In the next shot, the man is still behind her, but suddenly slightly closer. (01:53:50)
Continuity mistake: When Daniel is trying to take the OCTA CCTV guard's ID pass, he takes a picture of him with a Polaroid camera so that he can stick it onto a tag to prove that he is from a mental hospital. When the picture prints out from the camera, all that is shown is shown is the image of the guard against a white background, instead of the wall seen behind him. Also, when Daniel takes the picture, the guard has his head turned to the right to face Daniel, but when the picture prints, the guard has his head positioned completely forwards. (00:17:40)
Continuity mistake: When Walter is explaining his relationship with Owen to the Horsemen, Merritt's position changes whenever the shot is on him. He is either sitting on the couch with his arm on the arm rest and leaning forward, sitting with his arm on the arm rest and has his back against the couch or sitting with his back against the couch with his hand in his lap. (00:37:45)
Continuity mistake: Daniel is about to give the chip to Walter and Dylan rushes in to stop him. When Daniel first takes out the chip, he has it in his right hand, but when Dylan pushes him up against the wall, the chip is suddenly in his left hand. (01:11:15)
Continuity mistake: When Dylan is on the boat with Walter and Tressler, there is a bloody cut on his bottom lip, but when he is rescued by the Horsemen minutes later, the bloody cut has suddenly vanished. The cut reappears when Dylan and the Horsemen are talking in the next scene. (01:15:05 - 01:22:15)
Continuity mistake: When Jack is performing in London, there is a woman directly in front of him, recording him on her phone. In one shot, she has her left hand across the left side of the phone and is holding it, but in the next shot, she is only holding the left side with only two fingers. (01:29:20)
Audio problem: When younger Dylan is talking with his father before he performs the stunt, Dylan tells Shrike he doesn't want him to go and Shrike says to him "Dylan, come on. We talked about this." As Shrike says "Dylan, come on", the shot is behind him, but his jaw doesn't move with the speech. (00:01:15)
Continuity mistake: When the Horsemen are escaping the OCTA party, Merritt starts accusing Daniel of being the lead Horseman and removes the microphone headset he is wearing. The shot then cuts to an angle behind Merritt, and the microphone headset is suddenly back on his head. (00:25:40)
Continuity mistake: After arriving at the Macau casino, Chase starts teasing Merritt and Merritt then gives Chase the finger by rubbing his eyes with his middle finger. Merritt then begins to lower his arms, but in the next shot, his arms are suddenly by his side. (00:33:10)
Continuity mistake: When the Horsemen first see Walter Mabry, he is shown flicking a card between hands. Just before the camera cuts to a closer shot of him, he is seen with his head facing the window, but when the camera cuts to the closer shot, he is suddenly looking at the card. (00:34:15)
Continuity mistake: When Merritt and Chase are talking at the bar, they are sitting side by side facing the bar, but when the shot changes, they are suddenly turned 90° to face each other. (00:48:30)
Continuity mistake: When Dylan meets up with Daniel in Macau, Daniel tells him he cannot be seen with him. Daniel's hands are by his side, but in the next shot, he is suddenly has one hand on his ear. (01:08:55)
Continuity mistake: The analogue clock on the wall in Thaddeus' prison cell goes back in time by 5 minutes from 7:57 to 7:52. (00:42:10)
Continuity mistake: When Atlas walks in to the Octa phone launch disguised as a waiter he has a silver tray. Someone rearranges something on it as he walks down the corridor and it is plainly a silver tray. He walks through after the rearrangement and the next shot there is a briefcase visible under the tray. The tray is supposed to be a tray that becomes a briefcase but is too thin to do that. When first seen there is no space for the briefcase part to be closed up against the tray. (00:16:55)
Continuity mistake: In the first movie, when Dylan and Alma first meet up with Thaddeus Bradley for lunch, he mentions that Lionel Shrike was a magician in the 1970s and one year later, attempted the safe in the river trick that killed him, but in the opening scene of this movie, it is shown that the safe in the river trick that killed Lionel Shrike took place in 1984. (00:00:35)
Continuity mistake: When Dylan is showing the FBI director and Cowan the photo of who may be Merritt McKinney, he is standing next to the director turned to the right, but in the next shot, the two are suddenly directly facing each other. (00:08:15)
Answer: The only ones who knew the chip was fake were the Horsemen, no one else did. Walter did not know the chip was fake. The plan was to convince Walter that the chip was real so that they could lure him out of hiding with Walter attempting to kidnap and later kill them, and expose Walter to the public in doing so. They told the crowd after exposing Walter about the chip, because while it was a fake, they still had plans with it assuming it was real. If by "alert the FBI", you were referring to when Dylan gave the FBI director the evidence on Walter and Tressler, that was not the chip he gave to her, that was a hard drive containing all of Walter and Tressler's past dealings.
Casual Person