Frosty the Snowman (1969)

Continuity mistake: When Frosty gets off the train because Karen gets sick, from the magician's view it appears the train is slowing down and is very close to Frosty, but when the shot goes back to the magician, the train appears to be going much faster and is much further away.

Continuity mistake: When the kids are playing "follow the leader", they show the same kid (same exact clothing, hair color, and animation) hopping over Frosty twice, back-to-back. (00:09:37)

Other mistake: The narrator says that the train stopped to let the train filled with Christmas carolers go by, but the train passed after the train had already crossed the tracks, so there was no need to wait. (00:19:30)

Boy #1: What shall we call him? Should we call him Harold?
Boy #2: Uh, Bruce?
Children: No.
Girl #1: Christopher Columbus?
Children: Oh, no.
Boy #3: Oatmeal?
Children: Oatmeal?

Narrator: Frosty realised that Karen had to get out of that car as soon as possible. So when the little freight train stopped to let an express full of happy Christmas travelers pass, Frosty took advantage of the opportunity and quickly got them all out.

Narrator: Hocus explained the situation to Santa, who as you know, speaks a fluent rabbit. And, when they didn't find Frosty and Karen on the hill, Santa followed Frosty's path in the snow to the greenhouse. When they got inside, a terrible sight met their eyes.