
Double Dose - S2-E10
Factual error: Season 2 episode 10 "Double Dose": When Superman snatches Parasite's escape boat and hauls it back to Stryker's, Parasite attempts to blast him with a shotgun found aboard. But somehow the animators appeared unable to decide whether the gun should be a double-barrel or a pump-action type; and building a double-barrel pump gun would be impractical due to additional weight and bulk.

Fat Like Me - S5-E3
Factual error: When we see Tiffani and Stacy talk on the phone with Quinn (on the other end), we hear a call waiting beep from Quinn's end (but the camera still on the two girls' side) and Quinn mentions she's getting a call from Sandi. The mistake is only Quinn herself would have heard the "beep" and the other girls would have just heard Quinn's voice cut off with dead air for a second. Tiffani and Stacy should not have heard that "beep" like it was shown in the episode.

Fruit Picking Day/Daniel Is Big Enough to Help Dad - S1-E11
Factual error: Daniel's dad glues and screws the door bell button to Daniel's treehouse. He does not connect any wires to it or anything of the sorts, nor is there a power source to the tree house. Yet he pushes the button and the bell rings loudly. It is too small to house batteries or a speaker on its own. And the bell was electronic sounding.

Robo Koopa - S1-E52
Factual error: Koopa tries to kill the Mario brothers, Bunsun and Dr. Nerdnik by pushing an electric pole at them. Mario and Luigi use a nearby fire hydrant to protect them by having water rush out of it and keeping the pole from crushing them. There is no way a single blast of water can stop a large pole from falling, and the brothers would have been electrocuted as soon as the water hit the pole. (00:07:00)

Ruri chan 'Kôkai nisshi' - S1-E5
Factual error: The altar Yurika is doing a ceremony at contains Cyrillic writing that appears to be gibberish mixed with proper Latin words. (00:09:50)

Factual error: Dario Brando dies in 1880 (date on the gravestone) but when he was screaming at his son from his bed, Dio was reading "The Rise of Silas Lapham", which while being appropriate for his character, would be published only 5 years laters (started serialization in 1884).

Factual error: There's an exhibit in the Smithsonian Institute that shows Benedict Arnold, William Demont, and Major John Andre labeled as Famous American Traitors. One problem, Andre wasn't a traitor to America as he was a British officer to whom Benedict Arnold arranged to surrender West Point to during the war.

Factual error: Linda calls up Jen the babysitter to come watch over the Belcher kids, so she and Bob can go to Maya and Beckett's loft "party." Jen is in her room talking to Linda over the phone, however her screen still has the red (decline call) button and the green (answer call) button with Linda's name as she talks on the phone. There should only be the 'hang up' button with Linda's name and a running time of the duration of their call. (00:04:22)

Factual error: Semi-automatic pistols, rifles and fully-automatic rifles and machine guns never eject spent shell casings in the show.

The Secret of the Unicorn: Part 1 - S1-E3
Factual error: The man selling the Unicorn tells Tintin that he can have it for 25 dollars. Tintin is Belgian and this is in his home town; they should be using francs in that time period. (00:03:30)

Reptiles in the Rose Garden - S1-E1
Factual error: After the White House is teleported to the Mushroom Kingdom, the President can be seen still using his phone, but it would not work as it would be disconnected from the landline. (00:03:44 - 00:07:19)

Cell of Iron - S2-E3
Factual error: When Iron Man is floating away from the asteroid after his thrusters and repulsors have malfunctioned, he somehow comes to a dead stop in the vacuum of space. (00:07:27)

Welcome to Brickleberry - S1-E1
Factual error: Malloy has been missing all day and is starving from not eating. Yet his cheeks are sunk in like he hasn't ate for weeks. Your face doesn't get like that after not eating for a day.

Factual error: Brozzi asks for Lupin's help saying that the final of the Coppa Italia elimination tournament is in 3 days. He just played a game winning the semifinals, though; there is not, and never has been, such a small interval between the final stages of the cup. (00:06:20)

Factual error: Squirrels are seen woken from hibernation along with other animals, but squirrels don't hibernate.

What If... Captain Carter Were the First Avenger? - S1-E1
Factual error: When Stark starts telling about the Tesseract, the colonel shows surprise that Nazis were in Norway. Peggy answers with "Close. HYDRA." The scene is set in 1943, and Norway had been occupied by Nazi Germany for three years already. Them being in Tønsberg should not come as a great surprise to an Allied commander. (00:07:10)
Suggested correction: I feel like this falls under the "Not a mistake because it's an alternate universe" umbrella. We're in an entirely different universe with a different timeline in this episode.
The show also makes a point that the only difference should be the minor choices or events befalling the MCU characters, and how these minor things have huge consequences for them, basically creating a new alternate timeline. Basic world history before these events is not affected by the new timeline.
Basic, unaltered world history does not apply with this because we are talking about an alternate WWII from the beginning. One with Schmitt/Red Skull as propaganda minister of Hitler, Hydra superseding the SS, super soldier serum, Stark tech, the Tesseract, etc. It is not WWII as we know it, even without the "what if."

Factual error: The forces of Cassiopeia all sport the crown-like "W" sign which is the shape of that constellation... but only as seen from earth! These five points in three-dimensional space (like all star signs named after anything) look like that when viewed from our own planet; but from anywhere else, they aren't shaped like that at all. Why would they chose to see themselves through a very specific angle of view from some other distant planet (earth)?

Wax Doll Castle Murder Case: File 3 - S1-E9
Factual error: The culprit merely drops a chandelier from the ceiling in an unplanned move. From that simple action, the whole building - a huge castle - catches fire so quickly you'd think it's made out of papier-mâche soaked in gasoline, not stone.

The Origin of the Silver Surfer: Part 3 - S1-E3
Factual error: When Silver Surfer is battling Galactus just outside the Earth's orbit, Surfer is depleted of his Power Cosmic and looks to draw energy from the sun to replenish it. The sun is pretty close to the Earth's orbit, when in reality it is 93 million miles away.

Factual error: When the large Dutch guy tells his story about his life in Holland, there are a several windmills. However, the blades are placed on the wrong side, that way it's not possible for a windmill to turn clockwise, which it does. If the blades were placed correctly, they would still turn to the wrong side, because wooden windmills in The Netherlands are always turning counter-clockwise.