Other mistake: When Snoopy starts sneaking through the pumpkin patch, Sally is standing with her arms crossed and Sally's hand is painted blue while talking to Linus. (00:20:35)
Visible crew/equipment: As the Batcoper emerges from its hangar, multiple crew and equipment are reflected in the cockpit's glass bubble. (00:04:05)
Revealing mistake: When the stagecoach driver gets hit with an arrow, it springs up from below into a horizontal position. (00:33:55)
Other mistake: When the Grinch rides his sleigh back to Whoville and returns everything, as the narrator says, "He brought back their pantookas," a pink ornament lands on the Christmas tree, then changes to yellow mid-shot.
Continuity mistake: When Don Knotts is in the old Simmons mansion, he falls down a chute of some kind. If you watch closely you will see the stunt person looks nothing like Don Knotts. It is a younger man with very straight hair.