Other mistake: Anna is shown from the front as she ascends an ice staircase inside Elsa's ice castle. There are giant ice pillars to Anna's right and left. They should reflect the side of her face, but instead the reflections show her face from the front.
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Suggested correction: That's not how reflections work. The ice walls are about two feet to her side so the reflection would look like it was shot from the front but about 4 feet to the side.