Continuity mistake: When Trelawney asks Ron to look in Harry's cup and read the tea leaves, the Grim within the cup is visible. When Harry looks in the cup the Grim is different, for example, it has an open mouth in this shot. (00:30:20)
Continuity mistake: When entering the Hippogriff paddock, there is a shot of Hagrid stepping over the wall with the children behind and the ground is sunlit. Then it cuts to a wider shot and the ground isn't sunlit. (00:30:45)
Continuity mistake: During Hagrid's class, Vincent Crabe has his shirt outside his pants. He puts his things on the wall and when Draco and Harry are talking, his shirt is now half tucked into his pants. He didn't have the time to do that. (00:31:20)
Continuity mistake: When Malfoy shouts "Dementor. Dementor." all the kids turn around. Then we see Malfoy and some kids put their hoods on, and at the same time we can see Hermione turn back. When it cuts to Potter turning back we can briefly see Hermione turn back again. (00:31:45)
Continuity mistake: Before Hagrid's lesson begins, Malfoy yells, "Dementor! Dementor!" and they all spin around. Ron and Hermione stand beside one another in the first and third shots, yet in the middle shot facing Malfoy, they're a good distance apart. As a matter of fact, in most shots throughout this entire scene many of the students' positions and actions change and/or shift back and forth in consecutive shots, some quite drastically. (00:33:00)
Continuity mistake: In the paddock scene, Harry is walking towards Buckbeak. The shot then focuses on Hermione putting her arm on Ron's shoulder. Then the camera focuses back on Harry and in the background you can see Hermione placing her arm on Ron's shoulder again. (00:33:10)
Continuity mistake: During CoMC class, after Hagrid coughs, says, "Ta da!" and gestures toward Buckbeak, there is a shot of the students and Hermione's Monster Book of Monsters lies open on the huge rock. In the next close-up of Hermione, her book is closed and partially buckled. When Ron asks, "Hagrid...what is that?" her book lies open again. Books lying near Hermione's change in consecutive shots as well, including the one held by the girl beside Neville. (00:33:20)
Continuity mistake: At the start of Hagrid's lesson, he coughs and says, "Ta-daa!!" for all to see Buckbeak. In the next wide shot Goyle stands at the back and his hood and robe lie flat. In the next close-up Goyle's hood is positioned completely differently, then in the next wide shot it's flat again. (00:33:20)
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: Draco Malfoy starts eating an apple during Hagrid's lesson about Hippogriffs. During the lecture, his apple changes back and forth from having a few bites taken out to being whole again. Draco himself also moves in the background from shot to shot. (00:33:40)
Continuity mistake: During Hagrid's lesson, when Harry walks towards Buckbeak as Hagrid explains to Harry that he needs to wait for Buckbeak to bow back, etc., in the next shot a boy on the left of the screen drops his cloak to the ground. In the next shot of the students, the boy has it on his arm again, but in the next shot as Harry bows, it's on the ground once again. (00:34:10)
Continuity mistake: In the paddock scene, Harry's tie changes length. When he is in the paddock the narrow end of the tie is longer. When flying on Buckbeak, his tie is properly even. Then when he returns to the paddock, his tie is uneven once again. (00:34:15 - 00:36:50)
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)
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 the ghost comes through the window on his horse we see him riding into the hall before the headless ghost comes through the window and pursues the first ghost. Then it cuts from inside the hall and we see the first ghost come through the door again. By this time it should be the second ghost coming through the door, not the first. (00:37:15)
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: In the DADA class, when Lupin puts the needle on the horn gramophone disc to start the music, the position of his hand and the needle in the close-up differs greatly than in previous and following shots. Throughout the scene the gramophone and its horn's position differ in consecutive shots as well. (00:40:30)
Continuity mistake: When Neville magically makes the Snape Boggart wear his grandmothers clothes, in one shot the Snape Boggart clutches his red handbag with both hands by his chest, yet in the next shot he is holding the handbag down by his right side. (00:40:55)
Continuity mistake: In the boggart scene after Neville Longbottom has confronted the boggart, we can see that Ron is next, then Seamus Finnigan, then Parvati Patil. But after Ron's turn with the boggart, Prof. Lupin immediately calls out Parvati. Seamus never got a chance with the boggart even though he was right behind Ron. (00:41:10)
Continuity mistake: In the Boggart scene, right after Professor Lupin tells Parvati to go and face the Boggart and it shows Harry high-fiving Ron, in the background you can see Seamus start to walk towards the front of the classroom, but he is standing behind Dean Thomas seconds later in the next shot. (00:41:40)
Chosen answer: It's not known what it is. It is left to the audience's imagination of what exactly is in the room or what some witch or wizard was doing in there. This is only meant to be a humorous bit and is unrelated to the plot. It didn't happen in the book.
raywest ★