CoS - when Harry is running towards Ginny in the chamber, he's got his wand in his left hand (which is odd as he's right handed) but when he gets to her he drops it to the ground it's from his right hand

When Dobby is blowing his nose on his pillow case/dress/robe, there's no snot on it....I know that's a disgusting thing to notice, but I'm a naturally observant (and picky!) person

Also, there were the badges on the robes when they took the polyjuice potion. Earlier in the film, Malfoy's badge was quite clearly Slytherin so I would assume that all of them would wear the same, but it looked like a Hogwarts badge.