Continuity: How can Ron and Lavender be in a 'prominent corner' of the Common Room when in Harry Potter and the Philosopher's Stone, it says it is a circular room?

Continuity: On page 186 of the American hardcover, about a quarter of the way down the page, a paragraph begins "Malfoy looked rather as he had done the time Hermione had punched him in the face." He was never punched by Hermione in the books; in Book 3, she only slapped him.

Continuity: When Dumbledore arranges his first lesson with Harry, he asks Snape to postpone Harry's detention for a week. Since Snape never specified a time for said detention, Harry could easily have kept both appointments that night; especially since Dumbledore's lesson appears to take very little time.

Plot hole: In the first potions class, Slughorn shows them a few potions and says that these are some of what the students should be able to prepare after completing their N.E.W.Ts. But later on in the book, Ron asks Harry to check his textbook to see if they can prepare a stock of it for themselves. Harry says it's very complicated and that it takes six months to stew. If that were so, how did Slughorn prepare it for their first class? He barely had even 2 months since Dumbledore hired him.

Continuity: When Harry and Dumbledore are in the second chamber in the cave it says, "The greenish glow and the light from the two wands." There should be only be one wand lit which is Dumbledore's, because it never says Harry lights his wand, and it is illegal for Harry to use magic outside of Hogwarts because he is not "of age".