The Defection of Hawkeye - S1-E8
Deliberate mistake: When Mandarin is watching and wondering why Julia is tailing Clint, the road surface and cliff walls around Julia's car are recycled repeatedly. (00:10:55)
Deliberate mistake: There is a shot of Alexis getting blasted with electricity when Etoile Cyber is attacked by Sparkman. This same shot is reused later in the episode when she attacked directly by Elemental Hero Thunder Giant, as the electricity and Alexis' position in the shot is the same. (00:12:20 - 00:18:36)
Deliberate mistake: When the turtles and April escape the building filling up with water, the shot where the hall is filling up with water is used twice.
Formidable Enemy!? Mother Coordinator Enters! - S7-E37
Deliberate mistake: This Pokémon Trainer's Choice segment incorrectly claims that Arbok evolves into Seviper, which isn't true. (00:11:38)
Deliberate mistake: When Thomas goes by the level crossing, a close up of Thomas is shown but it's the same footage from season 1, only flipped. Because of this, Thomas' number is mirrored.
Deliberate mistake: In this episode, it is revealed Donna and Robert got together because Robert saved her from a water fountain. In "Another Bad Thanksgiving", it was shown Donna's sister introduced Robert to Donna. (00:02:20)
The Secret of the Unicorn: Part 1 - S1-E3
Deliberate mistake: After Francis Haddock kills Red Rackham, he lights a fuse to the explosives. The fuse that was lit is only a foot long, yet he is somehow able to climb out the ship without anyone noticing, get into a boat and swim all the way to land before it explodes. At a foot long it would have exploded in 10 - 15 seconds, all of that would taken at least 10 minutes. (00:18:45)
Deliberate mistake: When the sewer worker is trying to escape the Lizard, the fast lanes in both directions of traffic are visibly clear for several blocks, which is extremely unlikely in downtown New York. (00:01:10)
Winning Through Intimidation - S1-E15
Deliberate mistake: In the actual card game, attacking the castle ring would not be allowed, but this is probably done in order to enhance the show for kids.
Deliberate mistake: When Fluttershy is telling off the cockatrice, her back legs and her wings turn to stone. But when she gives it the stare and the camera is right in her face her wings are outstretched.
Deliberate mistake: There's at least two episodes (Season 1's "Captive Hearts" and Season 4's "Sanctuary, Part 1") in which a character shows video footage of the X-Men and various supporting characters in action, but the footage is merely clips from previous episodes.
Deliberate mistake: At Pete's diner, the owner puts the tray down, and instantly glasses appear in front of the 5 patrons. (00:02:50)
The High Life / Best Friends - S2-E10
Deliberate mistake: In "The High Life", there is a scene where Stinky submerges his head in a tank of water. He delivers the line, "Gee willickers, it's still ticking", and everyone somehow understands what he is saying with his head underwater.
Suggested correction: Nobody responds to what Stinky says, so there's no reason to assume that everyone understood him.
Episode XCII - S5-E1
Deliberate mistake: Jack stops his motorbike beside a stream, and Jack's weapon strap crosses over his left shoulder when he walks over to have a drink. The problem is when we see Jack's reflection in the water, his image is not reversed; note the strap is still crossing over Jack's left shoulder. (00:07:20)
There's A Demon Shark In The Froggy Dark - S1-E9
Deliberate mistake: Unless they're super strong, none of Mystery Inc could've thrown an anchor to the top of a cliff.