Continuity mistake: When Harry first arrives at Lupin's office as he packs, the skulls with the horns, sitting atop the bookcase, are visible. In the following shots, the skulls not only drastically alter their positions, the one with the very tall horns is actually gone in some shots. (02:07:45)
Continuity mistake: As Harry quickly flies off on his Firebolt, in the wide shot when he rounds the fountain, Percy, Ron and Hermione stand in front of Fred, George and Neville. However, in the next back shot Fred, George and Neville stand in front of Percy. (02:09:20)
Continuity mistake: When Harry arrives at Lupin's office the tall dark ornate chair sits directly in front of the corner of Lupin's desk, with one of its chair legs right beside the desk leg. However, in the wide shot when Lupin explains that he resigned, the chair is much further away. Then after Lupin leaves, when Harry walks towards the door, the chair is beside the desk again. (02:16:10)
Continuity mistake: When Marge insults Harry's parents, Harry gets angry and screams "Shut up." In the very next shot, from behind Petunia, Petunia turns her head behind to look at Harry. The next shot is a side on/wide shot and Petunia's head is not turned behind, in fact she is now looking in Vernon's direction. In the next shot, which is again a shot from behind Petunia, she is looking behind again.
Continuity mistake: The cuts including the one with butterfly closures on Hermione's cheek and the scratches on Harry's cheek change position/characteristics in many shots throughout, even in consecutive shots.
Continuity mistake: After bowing to Buckbeak, Harry removes the chain from the ring on the wood post, with the crow sitting on it. In the close-up, the wood post with its metal hardware, and the actual black crow, all noticeably differ from the previous and following shots.
Continuity mistake: In the CoMC class, when Hermione says "I think they're funny", you can see her Time-Turner outside her robes. When she turns to look at Malfoy, it's not visible anymore.
Continuity mistake: When the executioner goes to chop the pumpkin (the second time), you see Fudge reaching for a crow on his hat. In the next shot, both his hands are at his side.
Continuity mistake: When Harry and Hermione are back in time and hiding in the woods. Notice that Hermione has a bruise/sore on the bottom corner of her lip that keeps appearing and disappearing.
Continuity mistake: In the Time-Turner scene, when Hermione says, "Malfoy's coming," it shows her starting to jump through the archway before Harry. In the next shot, it shows Harry coming through first.
Continuity mistake: When Harry is about to pass out and says "Sirius", he says it in two breaths (Siri-us). The second time, when Harry and Hermione are watching this same exact scene occur in time, he says it in one breath (Sirius).
Continuity mistake: The position of the "little old lady at twelve o'clock" in comparison to the bus while she's crossing the street changes quite a few times.
Continuity mistake: The first time Harry, Ron, and Hermione leave Hagrid's hut before Buckbeak gets "executed," Hermione opens Hagrid's back door and all three are peeking out of it before Hagrid opens his front door. The second time, when Harry and Hermione are watching from the pumpkin patch, Hagrid opens the front door at about the same time that Hermione opens the back one, and Ron and Harry aren't even seen yet. Because this is the same event in time from two different points of view, it should be absolutely synchronized.
Continuity mistake: When Snape and Harry are in the hallway and Lupin shows up and Snape goes, "Well, well, Lupin," you see Harry in the background attempting to tuck away the Marauder's Map in his pocket. When Snape grabs for it, he reaches up more, as if Harry is holding it more by his shoulder.
Continuity mistake: When Ron drops Scabbers after Buckbeak has been 'executed', he and Hermione are very close together, note the position of their feet. In the next shot, when Ron says, "He bit me," Hermione is now standing farther away from him.
Continuity mistake: In the "Care of Magical Creatures" scene, Hermione gets a fright and there is a close up of her grabbing Ron's sleeve. From a different shot seconds later, you can see her grab his sleeve again in the distance.
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: During the scene in which Uncle Vernon's sister Marge is turned into a balloon we see her floating out of the conservatory. A second before she is blown out the door we see from the shot looking into the conservatory that Aunt Petunia is to the right of the conservatory doors inside the dining room. When the shot changes, she is now standing in the doorway to the conservatory.
Continuity mistake: When Harry goes back to Hogwarts and they stand before the Fat Lady portrait she refuses to let them in because she's trying to show them she can break a glass with her voice. When she cannot she smashes it upon a brick wall behind her right shoulder. Later in the movie after the students gather around the Fat Lady's painting after it's slashed the wall is missing.
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 ★