Continuity mistake: While Harry and Hermione try to coax Buckbeak to follow them, Hermione has the rope with the ferrets around her neck, which differs between shots. After Hermione tosses Beaky the second ferret, in the shot facing her she takes hold of one of the two hanging on the rope, on her left and dangles it, yet in the next wide shot she dangles both ferrets, in her hand. (01:54:15)
Continuity mistake: During the class with Hagrid, sometimes Ron has his Monster Book of Monsters under his arm and sometimes he doesn't have it. (00:33:35 - 00:34:55)
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: After Harry opens the front door for Uncle Vernon and Aunt Marge, Vernon walks into the living room and Harry follows him. Harry stops before he walks over the door step, but when it cuts you can see he has crossed over it. (00:01:55)
Continuity mistake: When Potter spots the dog at the bus stop he stumbles backwards and falls onto the pavement. Then we see the bus light come at him. When it cuts we see the bus come around the corner. How could the light be shining on him when the bus wasn't coming at him at all? (00:07:50)
Continuity mistake: When Tom pushes Harry to the chair you see him pushing with one arm only. When it cuts you can see him pushing with both arms. (00:12:40)
Continuity mistake: When Harry unbuckles the belt around the Monster Book of Monsters, the belt lies open, across the bench. As the book chomps at Harry, in the shot behind Harry's feet the belt is curled up on the floor, to the side of the bench. (00:15:05)
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 falls backwards onto the pavement, after seeing Sirius the dog, in the shot facing Harry the trunk lies halfway up on the pavement. However, in the next shot as the Knight Bus nears, only the very top edge of the trunk leans on the pavement. Yet in following shots it is halfway up the pavement again. (00:08:10)
Continuity mistake: During Hagrid's class, when Malfoy stands before Buckbeak as the Hippogriff rears up, in the wide shot facing Buckbeak, Malfoy lifts HIS left arm with his right arm still down at his side. However, in the next close-up facing Malfoy, HIS right arm is now lifted high up. (This has nothing to do with camera angles.) (00:37:55)
Continuity mistake: As the Knight Bus stops outside the Leaky Cauldron we see Stan Shunpike fold the newspaper as Harry flies forward. When it cuts we see Stan Shunpike fold the newspaper again right before Harry hits the window. (00:11:40)
Continuity mistake: When Harry falls back after being startled by Sirius the dog, the Knight Bus headlights shine glaringly bright light all over Harry and the trunk. Yet in the next shot facing the oncoming Knight Bus, Harry and the trunk are barely lit by the headlights, which are nowhere near as bright. In the previous shot the light is obviously provided by spots. (00:08:10)
Continuity mistake: The first time Dumbledore knocks on Hagrid's door, you hear him knocking three times. Later when Potter and Hermione have travelled back in time you hear Dumbledore knocking three times, rapidly followed by four more knocks. (01:21:55 - 01:47:15)
Continuity mistake: When Harry, Hermione, and Ron are hiding behind Hagrid's pumpkin patch in an attempt to hide themselves from Fudge and Dumbledore, Hermione turns around at the sound of a 'crack' in the forest, she then turns to her left and runs with the others. Later, when seen from Hermione's view reliving the past, Hermione at the pumpkins turns to her right before running with the others. (01:26:20 - 01:52:20)
Continuity mistake: When Trelawney is walking towards the table that Potter, Ron and Hermione are sitting at, you can see the book on the table is closed. When Trelawney gasps it cuts to Ron and you can see the book is actually open. (00:29:00)
Continuity mistake: When Harry and Hermione are back in time, Dumbledore, Fudge, the Executioner and Hagrid come out of Hagrids hut to execute Buckbeak and they find Buckbeak has gone. Then Dumbledore says "I don't think the minister's suggesting you had anything to do with this" and in the wideshot Dumbledore steps up onto the bottom step of the stairs leading to the hut, and stands right by Hagrid. Yet in the following closeup as Dumbledore says "How could you..." Dumbledore is now not on the bottom step, but standing on the path much further away from Hagrid. (01:50:10)
Continuity mistake: When the Whomping Willow kills the blue bird flying towards Hagrid's home, the loose branches from one shot are not visible in the second shot. (00:29:05)
Continuity mistake: When Ron gets Scabbers back in Hagrid's hut, immediately afterwards Hermione says, "I think you owe someone an apology". Later, when future Harry and Hermione hide behind the pumpkins by Hagrid's hut, you can see Ron getting Scabbers back. So right after this Hermione should be saying, "I think you owe someone an apology." But future Harry and Hermione talk for a little bit, and when they're done, Hermione says the line. Shouldn't this line have already passed? (This can be easily checked on the closed captioning.) (01:21:25 - 01:47:00)
Continuity mistake: After Potter and Hermione have escaped with Buckbeak, Dumbledore says, "I don't think the Minister's suggesting you had anything to do with it." At that time you can see three crows on the roof above Hagrid, and one of the crows takes off. When the scene cuts back there are still three crows on the roof. (01:50:10)
Continuity mistake: When Harry first reaches Lupin's office, as Lupin is packing, the Marauder's Map lies open on the desk. The map folds change position when Lupin says, "I saw you coming." (02:06:10)
Answer: This didn't happen in the book. It appears to be done purely for comic effect in the movie, showing Dumbledore's eccentric and quirky nature. He's seemingly oblivious to what he's doing and how it affects Ron.
raywest ★