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Revealing mistake: Watch as Hedwig lands on Harry's arm. It's quite obvious he has some protection under the shirt sleeve as his arm and wrist is unnaturally thick. (00:14:00)

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Revealing mistake: After Ron has been dragged down the hole by the Grim, you see both Harry and Hermione get hit by The Whomping Willow and they fly backwards and land on the ground. Notice when Harry places his left arm in the ground, the ground is unnaturally soft. (01:25:00)

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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)

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Revealing mistake: When Neville opens his 'Monster Book of Monsters' he falls to the ground. Then he is lying on the ground and his book is attacking him again. We can see the pieces of pre-cut papers, that should be coming out of the book's mouth, actually come up from the ground, when Neville is holding the book above him. Obviously it's not real. (00:31:15)

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