Audio problem: In the Knight Bus, when Shrunken Head says, "Yeah, take..." in the front shot, his mouth, cheek and jaw move as he speaks. As he continues, "...it away, Ernie! It's going to..." in the back shot, his mouth and jaw do not move at all, yet when he says, "...to be a..." his mouth and jaw move as usual. (00:09:20)
Revealing mistake: When they look at the newspaper about Sirius being sighted you can see the picture of Sirius on the newspaper doesn't move at all. (00:37:55)
Continuity mistake: In Hagrid's hut, Hagrid gets something from a cage, and then he tosses it for his creature to eat. If you look closely, you'll see Hagrid *accidently* throws the item over the creature, nowhere near its mouth, yet in the following closeup the item is still flying towards the creature's mouth, and the creature gobbles it up contently! (01:21:00)
Continuity mistake: When Harry puts his trunk on the pavement and sits down you can see him putting both hands to the ground. When it cuts while he is sitting down, you see him supporting himself on the trunk with his left hand. (00:07:10)
Continuity mistake: When Harry attacks Malfoy, he pulls Crabbe's pants down. When Malfoy and Crabbe start to run up the hill, in one shot, Crabbe's pants are down by his ankles. In the very next shot, his pants are up near his waist and he wouldn't have had time to pull them up between shots. (01:00:30)
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: After the Weasley's have handed over the Marauder's Map to Potter, George puts his wand on the Map while saying, "I solemnly swear that I'm up to no good." When it cuts to a closeup of the map, you can see the way Potter is holding it changes, and the way George's wand is on it changes. (00:57:25)
Continuity mistake: The angles, length and position of Harry's scar on his forehead, change considerably throughout the film. (02:00:25 - 02:02:05)
Other mistake: During the whomping willow scene, Hermione does indeed say Rupert, not Ron. She says it quickly, but I am not the only one who hears her say Rupert. She definitely does say Rupert. I just listened to it 3 times to make sure. [This may differ between versions - people are equally convinced on both sides.]
Audio problem: Near the Shrieking Shack, when Malfoy says to Hermione, "How dare you talk to me! You filthy little mudblood!" cloaked Harry whomps him with a snowball. In the next wide shot, Crabbe visually asks, "Who is that?" though no sound is heard. (01:02:15)
Revealing mistake: During the DADA lesson with the Boggart, the body double for David Thewlis (Lupin) is quite evident in some close range, head on and side shots. As a matter of fact, Emma Watson's and other actors' body doubles are very noticeable in many shots not involving a stunt. (00:44:15)
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: When Harry enters the Leaky Cauldron you see Tom bowing while stretching his left hand out. When it cuts he is holding his left hand behind his back. (00:12:00)
Continuity mistake: As Malfoy is approaching Buckbeak saying, "You great ugly brute," we see Hagrid turn around. Watch the dead ferrets hanging around his neck. They hang further down around his neck than they do in the next shot. (00:35:25)
Continuity mistake: When Malfoy and his friends take off, after Harry has beaten them, you can see Hermione and Ron standing in the background with their backs to a fence. When it cuts to a closeup of them they are suddenly standing behind a tree. (01:00:30)
Continuity mistake: As Vernon watches Marge float away, he is on his knees on the grass in the backyard, with Petunia beside him. Still on his knees as Vernon shouts, "Please!" in the shot from inside, his position on the grass is now centered with the door, so as to be visible for this shot. (00:05:50)
Continuity mistake: At the dinner table when Aunt Marge says, "You wanna try a little drop of brandy?" to her dog, you see Harry carry some plates in the background. When the scene cuts, he is standing with different plates in his hand. (00:02:45)
Continuity mistake: When Lupin is about to teach Potter the Patronus charm, you see Lupin walking with his hands in his pockets while saying "Do you have a memory? Allow it to fill you up. Lose yourself within it." When it cuts Lupin has his left hand up. (01:05:30)
Continuity mistake: When Sirius, Lupin, Snape and the rest are gathered together in the Shrieking Shack, in some of the shots we see the main double doors swing back and forth, due to light gusts of wind. However, the doors' positions instantly change in some consecutive shots, even though there is no wind between the two shots. (01:27:35 - 01:30:45)
Continuity mistake: At the hotel, when Harry tries to catch the Monster Book of Monsters, a train passes and some wood powder falls from the ceiling but when Harry steps on the book, there's no more trace of powder on the floor. It can't be completely under the book, because there was powder at different places. (00:15:15)
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 ★