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 is cutting Max's antler, the pieces that have fallen on the floor suddenly jump several inches closer to Max.
Other mistake: Fred's tie gets unraveled when he and Barney are trying to escape the Green Goose's dungeon. Yet, his tie is fixed a few minutes later.