Character mistake: When Olivia and Dr Galina are in the bathroom, Galina mentions an umbilical chord, from a baby whose mother died (Nadia), that contained Olivia's mitochondrial DNA. Mitochondrial DNA comes from the mother, so Nadia's Mitochondrial DNA came from Letha who got hers from Marie, absolutely nothing to do with Olivia.
Revealing mistake: When Kyle, Elizabeth and Robin are in the truck being chased by Mr. Chiang, in all the outside shots of the truck it is very easy to see that all three of them have been replaced by doubles. (00:09:05)
Continuity mistake: When Raven telekinetically reassembles the broken chime bead necklace, it has about nine beads and is rather tight, but before and after that the necklaces feature about 13 or 14 beads and are wide enough to fit around the others' necks.
Deep Metal - S3-E2
Continuity mistake: Depth Charge fights Rampage on the beach. Throughout the whole episode, Depth Charge has four fingers. But in a shot when DC doubles over in pain to clutch his wounds, he has five fingers.
Heads Of Beef / Klub Katz - S1-E11
Factual error: In "Klub Katz" the captian yells "Iceburg, Iceburg, on the starboard side." But when you see the iceburg and the ship, the iceburg was about to hit the bow of the ship.
Other mistake: When Spike is thrown out of the base by Megatron at the end of the episode, Optimus calls him 'Splik'.
Factual error: In episode 17 there are some scenes showing sick 4400s all around the world. One of them is being carried into an ambulance car in Frankfurt, Germany. The ambulance car's number plate begins with the letters FM meaning Frankfurt am Main. The correct abbreviation for Frankfurt am Main on German number plates is F - not FM.
Thrill Kill - S5-E1
Factual error: When Dylan gets out of jail, a palm tree can be seen in the background behind him. This reveals that the scene was filmed in Los Angeles, not Philadelphia.
Continuity mistake: When the professor stands up in the holding cell after Jack tells him that someone saw Skye at 10:30, he slams his chair back causing it to tip over. In the next shot the chair is upright, then when he goes to sit back down, it is again on its side.
Mainstream - S3-E3
Continuity mistake: When Kitty goes to get a midnight snack, her hair is down. But a few shots later, her hair is up in a ponytail.
Continuity mistake: When they first bring the girl to the house with the storm and lay her on the bead the there candles next to her. First the tallest one blows out then the middle one blow out then the shot changes and the middle candle blows out again.
Continuity mistake: Episode: "Man Hunt": When Jonas tries to interrogate the hardware store owner, the owner falls off his chair, knocking it over. In the next shot it's standing upright again.
Mommy's Little Monster - S2-E7
Continuity mistake: Miss Kringle's head is canted up and to the right as she lays on the gurney in the morgue refrigerator, but when Edward Nygma pulls her out, her head is facing straight up. Subsequent shots of her in the refrigerator her head is canted up and to the right.
Slave Island - S1-E7
Plot hole: After Storm's attempt to escape the Genoshan prison is thwarted, she ends up in the ocean right at the shoreline of the beach, where she is captured by a Sentinel. Aside from the fact that it makes no sense for a Sentinel to be hiding in the ocean in the event that a mutant tries to escape the prison, there is absolutely no way that a two-story tall robot could hide in the ocean right by the beach, as the water would be way too shallow. You can even see that the water level only goes up to the Sentinel's ankle area when it is standing upright in the ocean. (00:03:15)
Suggested correction: Perception. (1) The Sentinel isn't as close as it appears. If it were close, then she would have been caught in its waves as it emerges. Also, she would be looking only at its chest circle. It's several yards away. (2) She washes ashore. She fell from the sky. She couldn't have fallen from that great height into shallow water without hitting bottom. (3) It's also a two-story tall robot. Its weight would sink it into the sand. So it could have very well been down that deep.
Attack Of The Mutant (1) - S2-E2
Other mistake: In part 2, it was revealed that Libby was really the Masked Mutant all along but, in one scene in this episode, Libby is sitting next to Skipper while the Masked Mutant is standing on top of the bus.
Episode #1.4 - S1-E4
Continuity mistake: When Samuel and Marina kiss for the first time, she leans in towards her left. In the next shot, she's still kissing him, but leaning on her right side. (00:23:45)
The Agent Of Year Zero - S4-E14
Revealing mistake: During the scene when Mr. Lyle is talking to the General (butcher character), his glove that he wears on his hand is removed to make a point about his thumb having been cut off. In the next shot, we see Mr. Lyle walking around the desk and putting his glove back on, and you can see his thumb folded under his hand as if the actor was trying to hide it and did not realize it could been seen from the camera angle.
Continuity mistake: When Anne and Evert are driving toward the Norwegian/Swedish border, Anne pulls back the rug in the back of the sled, and discovers the dead Bjørn. He is then flat on his back, staring upwards. Moments later, when the Swedish border guards pull back the rug to look at the corpse, he is face down. No one touched him, and the sled did not bump enough to roll the body completely over.
Factual error: The bad guys are supposedly auctioning off the stolen Mona Lisa. But they and their prospective buyers aren't very art savvy. The painting is more than twice the size of Da Vinci's actual masterpiece. (00:44:50)
Continuity mistake: When the lab equipment shorts out after the earthquake, the unconscious Major Brothers is lying with his head propped up against the wall. But when Hamilton reaches him in the next shot, he's suddenly lying flat and is nowhere near the wall. (00:21:45)