Continuity mistake: During the whack-a-robot game, a big chunk of the broken robot lies on the counter, but it disappears a shot later.
Continuity mistake: After jumping off the roof, Mulan smiles at her dad while neighbours walk away, and a strand of hair falls over her forehead. A shot later her hair is brushed. She didn't move between shots.
Continuity mistake: When the Grand Witch throws the lectern, it lands 6 meters away from the chairs. When the shot changes, it's barely 2 meters away (note the wooden planks on the floor).
Deliberate mistake: In the Spanish release, the name of the family store is written in Spanish, but inside the place it's in English everywhere. This is a very common mistake in foreign kids' films released in Spain.