Other mistake: After the song 'Love Will Find a Way' when Kovu and Kiara are peering into the water and Kovu says, "We are one," in the reflection the scar on Kovu's face is on the wrong eye. Nothing to do with it being reflected, it was on the eye nearest Kiara, and now it's on the other eye.
Other mistake: During "Can You Feel the Love Tonight?", Simba's reflection in the water isn't very consistent - the rocks he's standing on are much closer to the water than they appear in the reflection. (00:58:45)
Other mistake: In the song "A Rumor in St. Petersburg," according to the closed captioning, the characters sing the words "no proof of fact." According to the lyrics in the soundtrack booklet, they are actually singing "or through a crack." And if you listen, it's actually what they are saying.
Other mistake: When Fievel And Tony reunite on the streets of New York, Tony gets a piece of cheese off of a mouse trap. Watch that piece of cheese, cause Tony throws it up in the air, and you never see it come back down. (00:33:25)
Other mistake: Wouldn't flying out of the water with the unconscious Z in his arms be kind of tricky for Cutter, as his wings would be soaked?
Other mistake: During the climactic moment when they're defeating the book, Jason shoves the key into the lock, sealing the evil within. However, he shoves the key into the lock upside down.
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: Merlin says, "Man will fly someday". For a few frames after he says this, his thumb on his pipe is painted blue, then returns to its normal color. This causes a blinking effect.
Other mistake: Just after the valley floods, Manny is seen pushing a log to pry the rock out blocking Ellie's way out. You can notice that Manny is pushing it the wrong way. (01:08:40)
Other mistake: In the scene where Andrea is being sucked into the fan at the Gotham worlds fair, Batman rides in on his motorcycle. He turns into the fan to rescue her, but his cape is flapping in the opposite direction in which the fans are sucking.
Other mistake: In the beginning the guy cuts a triangle in a banner, but the inside piece is floating.
Other mistake: When The Chipettes perform their audition for Ian Hawke they are standing on the Jett Records sign on the roof of the Jett Records building. In order for the sign to read correctly from the street, Ian and The Chipettes should have a backwards view of the lettering. In the movie the sign reads correctly from Ian and The Chipettes point of view, meaning that it is giving a backwards view to the street, ie. it is the wrong way round.
Other mistake: While Iago talks to the Oracle, when he flies towards her, he's seen not flapping his wings; he's just floating.
Other mistake: The size of Dave's sub is too small for all the rooms it contains especially the cargo hold with hundreds of penguins and cages.
Other mistake: When they first arrive at the North Pole, one of the elves appears to be sliding along. His legs and arms are not moving, and his head is not bobbing up and down.
Other mistake: Just after Grandma Willow says "There's still some snap in these old vines," John Smith puts on his bag, but he just presses it to him instead of putting it over his head.
Other mistake: When Kit Mambo prepares to catch up with Renè Fromage, she first overtakes two guys (the raccoon and the bighorn sheep) on 'third and fourth positions' - as announced by Barbara Warbler, then she passes the sheep and the camel before she catches up with Renè. This would place her first competitors on positions five and four, instead of three and four.
Other mistake: Near the end of the film when Jack-Jack is manifesting various abilities, his first display is of the human-torch-type of superpower. This would have burned away all of his clothing, yet (for obvious reasons) his diaper remains intact. This is particularly apparent as designer Edna Mode's costume for Jack-Jack was earlier shown as fire-resistant, but he was not dressed in his outfit during this scene. (01:44:15)
Suggested correction: This is definitely intentional, not an error. We see Jack-Jack use his fire powers without burning his diaper in Incredibles 2. Having fire powers without burning clothes is just a retcon.
Other mistake: When Ponies are flying back home from North Pole, you can see Cotton Candy among them. as a pegasus.
Other mistake: Throughout the movie large footprints of heffalumps are shown. However, when the heffalumps bound around, they never create any footprints of any kind.