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)
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.