Continuity mistake: After the Mad Hatter has finished filling the pocket watch with food, the watch starts flipping about and going mad and as it spins and flips, you can see the face of the watch has disappeared. (00:47:15)
Suggested correction: After the Mad Hatter has finished filling the pocket watch with food, the watch starts flipping about and going mad as it spins and flips. You can see the face of the watch has disappeared. When the March Hare breaks the watch with a hammer, the technicolour changes to grayscale.
What is this supposed to be? It's a repeat of the mistake with an added sentence that doesn't dispute the mistake. And the colour switch may have been intentional.