Revealing mistake: When String uses Airwolf's rotor wash to blow over the pickup, when the camera is on the truck, you can see a cable pulling the truck up from the right side.
Continuity mistake: When James is taking pictures from a car as men are entering a hotel, in the shots of him head on he is using a Canon EOS camera with a 70-200mm white lens. In shots from the side he is using a Nikon camera with an older Nikon lens. (00:27:35)
Other mistake: In the hotel room shootout, bullets are being fired through the wall easily and tearing up the place as you'd expect. Frank then dives through the damaged wall and they shoot at each other with Frank behind a cupboard and Pilgrim behind an internal wall. But bullets empties into both of these bits of flimsy cover leave the men behind them miraculously unscathed.
Visible crew/equipment: [Unsure episode] When Judy proceeds to flip K.C. over, you can see a boom mike at the top of the screen, which K.C. narrowly misses.
Continuity mistake: As they are fleeing the alien base, Supergirl and the others run towards the portal, Winn activates it and jumps through. In a following shot (after a 'friendly' alien helps them), he is standing behind Supergirl again. (00:32:00 - 00:32:35)
Extinction - S4-E1
Character mistake: Happy determines that the nitrogen hydroxide ate through the drum because it was "steel alloy," in contrast with Walter's requirement that it be "pure steel." These terms are inaccurate, and would not be used by technical experts like Happy and Walter. Every steel is an alloy, combining at a minimum iron and carbon; steel with other alloying agents is called "alloy steel," not "steel alloy." Because steel doesn't refer to one specific substance, "pure steel" could never be used to specify a material for a given application.
Revealing mistake: Towards the end of the episode she picks up her phone but the screen shows the incoming call still coming through, and the screen doesn't go dark when she puts it to her ear. (00:29:30)
Chapter 7: The Reckoning - S1-E7
Plot hole: The boss of the boss murders Werner Herzog because he knows that the baby is not in the crib. Yet it takes Mando's message (somehow intercepted) for the troopers to start moving in pursuit. The heck were they waiting for? They have overwhelming forces in the area and a previous deal with Karga. (00:33:10)
Factual error: When Tom has decided his scout group will have to go for the food and then his look for his son later, they are stood on a green. There is a war memorial dedicated to both World Wars, 1914 - 1918 and 1939 - 1945. That's got to be in Canada, as the USA didn't enter either war until later than those dates. (00:28:00)
Continuity mistake: In early versions of the episode, Luz is shown wearing her Hexside school uniform before she even receives it. This mistake spoils the ending. Fortunately, it was fixed later on. (00:00:01 - 00:00:40)
Character mistake: Trivette hands the man in yellow a bullet recovered from the plane Walker and Alex were traveling on, which was shot down by an assassin flying a P-51 Mustang. This man, and later Trivette, mistakenly refer to the round as a "50mm," when in reality, Mustangs were equipped with M2 Browning .50 Caliber (12.7 mm) machine guns. (00:30:25)
Factual error: When Ulysses opens his mouth while speaking, modern dental fillings are in his teeth.
Continuity mistake: Tenaya 7 is running on the treadmill in flat sandals with tan straps, she then has flat sandals with black straps as she fights the guards.
Character mistake: Referring to the US, Russian and Chinese governments, the admiral says that "Washington, Moscow and Shanghai" have been informed. The capital of China is Beijing.
The U.N.C.L.E. Samurai Affair - S1-E27
Revealing mistake: Mark's stunt double in the final fight scene has a very bad (and obvious) brown wig. Mark's hair, however, is blond. (00:44:00)
The Dog Who Knew Superman - S2-E9
Other mistake: A gangster pushes a dog into a well and the dog can be heard splashing around. The man's wife is furious and several people are unable to retrieve the dog. Superman tunnels into the ground and into the bottom of the well and emerges holding the dog. Both he and the dog are completely dry.
Continuity mistake: When Riggs is hanging from the tree, his hands are tied behind his back. When he falls and lands on his back, his hands are still behind his back. In the next shot of him, his hands are now tied in front of his body, even though he didn't have time to do anything to get his hands there.
A Sentimental Journey - S1-E19
Revealing mistake: Dialogue in the episode specifically mentions the A2 and A282 roads near Dartford, Kent - the actual roads used were the A1 Barnet by-pass, Galley Lane and Well End Road. The error is revealed by the sight of a road sign that appears just as the Austin Princess Limousine turns on the the main road - the sign shows that the car is not turning on the the A2/A282 near Dartford, but the A1 at Barnet some 40 miles away.
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: The first four episodes of season two have absolutely no continuity with the show. Prime examples are the fact that Shendu exists again as a statue which had been confirmed to be destroyed in "The Day of the Dragon", the final episode of season one. Next during "The Warrior Incarnate" it is mentioned that not all the talismans were in fact present, such as the dog talisman, when all talismans must have been found, or the events that escalated during the final episode of season one would never of happened. This problem is the extended during the next episode where Jackie Chan discovers the snake talisman in some sort of Brazilian temple - he had already learned of the snake talisman by stealing it from the museum quite early on in season one. The final continuity error is that Tohru goes from friend to foe and then back to friend as if the first four episodes of season two never happened.
Suggested correction: These were "flashback" episodes, not "they never happened" episodes.