Factual error: The story is set in 1976. "Funkytown" is used in the movie and the end titles. The song was not released until 1980.
Continuity mistake: In the beginning of the movie, Mavis stares at the window. When Drac sings to her, the window is closed in the first shot, but in the next shot it's opened. (00:01:00)
Factual error: In the timelapse footage showing the street outside Bob's Restaurant, the shadows are moving in the wrong direction. In the northern hemisphere, shadows go clockwise. (00:13:46)
Continuity mistake: In a pivotal scene in the middle of the film, Josh and his stepmother Constance are having a conversation about how Lyle has helped Josh adapt to life in New York City. In the background, the same woman can be seen walking past them multiple times. She is wearing an open gray sweater with an orange shirt.
Factual error: Robert and Giselle have their belongings shipped to their new home at "18 Honey Bee Trail, Monroeville NY 10960." Monroeville is fictitious but the 10960 ZIP Code belongs to Nyack, New York. (00:00:04)
Other mistake: When Jaeger is teaching Searcher how to throw. Through the scene Jaeger is handling Pando without gloves and Callisto is wearing fingerless gloves while also handling Pando. They should both have been shocked by the energy from the Pando. Jager is not immune, as he and Searcher are both shocked later by the Pando roots while using pickaxes to free the pando roots from the creature's heart later on in the movie.
Factual error: The film gets basic physics wrong while trying to depict relativity. Buzz Lightyear leaves T'Kani Prime for a trip around its sun, travels with near-light speed, and returns four years later. This could only have happened if T'Kani Prime's sun were at least two lightyears away! It gets more ridiculous. Buzz's last trip takes 26 years, even though he has traveled at faster-than-light speed. Overall, T'Kani Prime is experiencing either a mysterious time slow-down or a rapid orbit expansion.
Continuity mistake: The night Krypto loses his powers, he gets a black eye on his left eye. However, the next day, the wound is gone.
Continuity mistake: The view from the (unseen) car driving toward the distant house on a hill showed fog well above the pine trees, but when the car/limo got to the house/mansion (10 seconds later), there was no fog. (00:02:17)
Revealing mistake: This happens in the second ceremony when Wolf didn't press the button to shut off the lights to steal the golden dolphin because of the good comments. Few seconds later, the lights shut off, and you can see that the meteor on the top disappears at the time.