Revealing mistake: Very obvious copy and pasted dogs (even standing in the same position) whenever there's a general view of a crowd in the main hall.
Revealing mistake: Angelica and the other children are about to crash through the door to attack Lyra and Will. As Lyra runs past a cabinet, a lamp sitting on top is knocked over and crashes to the floor. Dafne Keene, who plays Lyra, reached over and very obviously pushed the lamp to the floor.