Continuity mistake: Just after Ron pushes Harry toward Buckbeak, the hippogriff is seen defecating. In shots after this, the hippogriff's droppings have altogether disappeared.
Continuity mistake: After rescuing Sirius, Harry and Hermione return to the hospital wing as the bell starts to chime. They make it up there before the bell is done, despite having to run up at least five stories. Don't you think that's a bit too fast?
Continuity mistake: In the Boggart scene, Lupin jumps in front of Harry to stop him from facing the Boggart. Between the shot directly before he jumps and the shot where he jumps, there is a dramatic change in his hairstyle. (00:42:20)
Continuity mistake: When Tom and Potter arrive in the Minister's office Potter goes straight to Hedwig. When Tom says, "He arrived here just five minutes before yourself." you see Potter touch Hedwig's beak. When it cuts he is touching Hedwig's cheek. (00:12:30)
Continuity mistake: When Potter, Weasley and the other kids are making all the animal noises and Potter makes the steam come out of his ears, we see Potter put his arms down. When it cuts from the outside we see Potter has his right arm up. (00:27:15)
Continuity mistake: In the first scene when the stone hits the jar of seed in Hagrid's hut, Hermione picks it up behind the shattered jar. Later when they have gone back in time, the stone lands next to the shattered jar among the spilt seeds. (01:21:30 - 01:47:00)
Continuity mistake: When Potter and Hermione is following back in time down to Hagrid's you see Hermione leaning against a column before putting her arm down. When it cuts back she is still leaning against the column. (01:45:25)
Revealing mistake: When Malfoy and his friends are messed with by an invisible Harry, Malfoy is dragged along by Harry. In the SECOND shot, when Malfoy is dragged along (which is a closeup shot of Malfoy's legs up in the air) pay attention to the bottom right corner of the screen, and you can see a bare hand quickly move into view, quite close to the screen. This can't be Malfoy's hand because he has gloves on. Slo-mo is not necessary to see this. (01:00:15)
Continuity mistake: When Aunt Marge is round and everybody is eating, in one shot Dudley is spooning something off of his plate, yet in the following shot his spoon is up in his mouth. (00:02:25)
Continuity mistake: During the DADA lesson, as Lupin jumps between Harry and the Boggart, to their right there are two tall containers, beside one another, standing against the wall with different items in them. The items change in the following shots, including the 'mirror reflection' shot. When the balloon whizzes past the back of the class and the camera spins around, the two vases are much farther apart, but in the next shot facing Harry, they're together again. (00:44:05)
Continuity mistake: Watch as Harry drops his shoe to the floor from the bed. You can see the shoe change angle between the shots. (00:15:20)
Factual error: When Harry is beating up Malfoy and the two Slytherin boys in front of the Shrieking Shack, he grabs one of them by his scarf and rotates him around. The center of their revolutions should be at the end of the scarf (where Harry grabs it), but as there is no actual counterweight for the boy he has to balance only his own body, which moves the center of his revolution strongly towards him. (01:00:10)
Continuity mistake: In Divination, as Trelawney says, "The art of crystal gazing is in the clearing of the Inner Eye... Now what do we have here?" Ron sleeps with his elbow at the books in front of him and then wakes. In the next shot the books are between him and Hermione. (01:19:15)
Continuity mistake: When Stan Shunpike says, "Take it away Ernie," we see Ernie having a bite of his toast. He then puts his hand with the toast down to put the bus in gear, but when the view cuts back the toast is suddenly gone. (00:09:20)
Continuity mistake: The large hutch behind Vernon actually moves over to the left, closer to the lamp, during the dinner with Marge. At the start of the dinner scene, the chair beside the hutch, behind Vernon, is at least two feet away from the small table, which holds the lamp. As Marge starts to expand, the chair is right beside the table. (00:02:40 - 00:04:25)
Continuity mistake: When Uncle Vernon is pouring brandy to Aunt Marge we see Harry picking up a plate from the floor while holding two other plates in his left hand. When it cuts Harry is still holding the two plates, but something which appears as a napkin or something has appeared in his hand as well. You can see it sticking out between the plates. Whatever it is it wasn't there in the previous shot. (00:02:40)
Continuity mistake: As Harry is about to drop his shoe on the floor in front of the Monster Book of Monsters, there is a closeup of Hedwig sitting on the chair. When it cuts to a wide shot, you can see that Hedwig has moved to farther to the left on the chair. (00:15:15)
Continuity mistake: When Harry, Ron and Hermione first exit Hagrid's cabin to get away from the ministry, they wait a lot longer at the door before running away, than when Harry and Hermione go back in time. (01:22:20 - 01:47:25)
Continuity mistake: In the shots facing Harry, when he unbuckles the belt around the Monster Book of Monsters and when he lifts the book to look at it, the wood box on the dresser near the the water pitcher faces the fireplace. In the rest of the shots it faces the bed. (00:14:30)
Continuity mistake: When Lupin is turning into a werewolf and Sirius comes at him while saying, "Remus, my old friend. Have you taken your potion tonight?" Lupin's shadow on the ground change position in the next shot. (00:35:20)
Chosen answer: Fred and George used the map to aid them in their mischievous activities at Hogwarts, and probably had little interest in what their little brother was doing or who he might be with at any given time.
raywest ★