Continuity mistake: Millie's beads have a mind of their own. They do not stay in place even when she is standing still. Besides the funny scene during the title credits (when it is deliberate), and when Miss Dorothy registers, they also move during a scene when Millie displays her thoughts on Miss Dorothy's beads when the two of them go into the elevator for the first time.
Continuity mistake: The elevator that Millie and Miss Dorothy use changes from an elevator to a small room with the walls of the building missing and the door as well.
Continuity mistake: When Mrs. Meers welcomes Millie for the first time, the position of her hands on the counter is inconsistent in every shot.
Continuity mistake: When Jimmy falls off the ledge, he falls backwards, slightly facing to our left. An instant cut later, he has magically turned 180° and is now facing our right, ready to safely grab onto the pole.