The Pieces of Fate Affair - S3-E23
Deliberate mistake: Because lawyers for real-life review columnist Judith Merrill were not amused by the parody of her and sued, the name Judith Merle is very obviously dubbed over throughout the episode (and changed in the credits) to Jody Moore. (00:32:50)
Deliberate mistake: Many of the Rangers in the Legendary Battle could not be there since they were portrayed by the same person. All 3 Rockys, all 3 Adams, and both Jasons and Kimberlys were all present.
Deliberate mistake: When Mephisto's true form is reflected in the concave side of the spoon, the reflection is right side up. However, reflections in the concave side of spoons appear upside down. This was likely done deliberately by the VFX artists to make this an easier Easter egg for fans to spot.
Deliberate mistake: Throughout the episode, all the police station clocks are still and show the same time (3:33) in different scenes. (00:18:55)
The Stadium - S1-E8
Deliberate mistake: The Korean lady's Mini-Uzi never runs out of ammunition, and she's spraying it at full-auto. A Min-Uzi's cyclic rate is 950 rounds/min. One long squeeze of the trigger and the weapon's dry. Same goes for all the other weapons like the M4 carbines being fired on full-auto, they have the infinity ammo cheat code going here.
Deliberate mistake: Probably best for filming the scene, but Jennifer Hart pulls up and parks her car on the street on a red curb in front of an ambulance and walks away. (00:10:12)
Deliberate mistake: As usual when the Hulk reverts back into Bruce Banner, he is left wearing nothing but tattered pants. When Mitch McCutcheon sneaks Bruce Banner into the nuclear research facility, Banner is shown wearing his usual outfit of a gray collared shirt tucked into purple slacks that are intact. Given that the Hulk was just in the middle of the Nevada desert, Bruce Banner would be in no position to have a change of clothes on him, and the idea that the top secret facility would have an exact match of his go-to outfit is ludicrous.
Deliberate mistake: The Seal takes a shot with his suppressed pistol through a circular window in the hull of the ship at a hostage taker holding a hostage. When he fires through the glass it never breaks or shatters. Makes no sense how the bullet even passed through. In addition, windows in ships are really thick; it would've taken a few shots to get through and to neutralize the hostage taker. (00:33:30 - 00:34:30)
Deliberate mistake: Inside the home that has been infested with Evil, the state police confront a possessed girl who attacks them. After some futile gunfire, the possessed girl is still standing. The female officer goes for her backup gun, which for some reason is a small over-and-under Derringer (meaning she has two shots maximum). She ends up firing the Derringer five times in just a few seconds, with explosive damage and without reloading. Director Sam Raimi probably staged the 5 gunshots on purpose, knowing that a two-round Derringer was a ridiculously-limited piece of firepower. Raimi probably did this as a tongue-in-cheek tribute to Ash's bottomless double-barrelled shotgun from Evil Dead 2 and Army of Darkness.
AKA The Sandwich Saved Me - S1-E5
Deliberate mistake: Kilgrave tells a man to throw a cup of coffee in his face, which he then does. Due to how hot the coffee was, it leaves the man in severe pain. The coffee cup was fairly small, had no lid and was exposed to the cool air, so even if the coffee had been boiled recently, it should have cooled down fairly quickly. (00:10:25)
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: 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.
Deliberate mistake: The last season touched on Infinity War happening - this season jumps forwards a year, meaning that we should be one year into the "blip" (or snap), with half the universe missing. But The Team is all together, and the world/universe is utterly unaffected. Largely a byproduct of disagreement between the film and TV sides of Marvel, plus scheduling vagueness meaning they couldn't risk spoiling Endgame if they came back on the air before that was released. But considering the show is 100% part of the MCU, that's a pretty massive contradiction.
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: During the episode, whenever daily newspapers are shown, they lack any indication of the date.
Deliberate mistake: When the show premiered on March 18th, 1981 Ralph's last name started out as Hinkley, but after a couple of episodes had aired on TV, on March 30th a man named Hinckley shot then U.S. President Reagan and three other people, so in the remaining episodes of season 1 Ralph's last name was changed to Hanley. His last name was changed back to Hinkley in season 2.
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.
The Night of the Tottering Tontine - S2-E16
Deliberate mistake: The knife that has just killed one of the investors doesn't have a trace of blood on it. No one had time to clean it off. (00:20:00)