Audio problem: At the end of the elf concert, when Mrs. Claus walks right out right after Santa does, we hear the sound effect of a door slam before she even closes the door. (00:13:40)
Other mistake: In the opening credits, when it pans to the yellow card showing the names of the songs that Burl Ives sings, his name is spelled "BURI" instead of "BURL".
Continuity mistake: While the misfit toys are singing "When Christmas Day is Here," the camera pans behind Cornelius, Rudolph, then Hermi. When the camera returns in front of them right afterwards, their order is reversed.
Continuity mistake: Sam's (the Snowman) pocket watch never advances past 2 o'clock from his introduction at the beginning of the movie to the end.
Continuity mistake: Before the elf choir sings for Santa, the Head Elf begins the countdown with his left and right index fingers, then suddenly there is a baton in his right hand as the choir begins singing.
Audio problem: In all post-1998 releases, the audio from the original 1964 ending (where the elves drop boxes) is used over the visuals of the refilmed 1965 ending (where the elves drop Misfit Toys). The "swoosh" sound from the old ending (being the sound effect from when the boxes were dropped) is heard multiple times and is not in sync with anything happening in the refilmed scene.
Answer: It's a kid's show, not Game of Thrones.