ployp

Continuity mistake: When we first see Hermione on the train, her tie is crooked. When she sits down, as Ron is about to change Scabbers yellow, her tie is straight and it remains that way while she is seated. When she leaves and turns around to tell Ron about the dirt on his nose, it is crooked again. (00:36:05)

Janice Ludington

Continuity mistake: When Harry is in the potions class he is caught writing notes down, we see his neat writing in close up ... but when the camera angle changes we can see that the writing has changed in size to very large letters and quite messy writing. (00:52:10)