Other mistake: The sign behind James Franco on the mirror behind the bar says, "Dinner Service Until 10pm". It's a modern paper printout and also a modern font, from a personal computer / printer which nobody would have at that time. (00:07:00 - 00:08:00)
Audio problem: Right after Carol finishes studying by singing a rap to Katie, Katie congratulates her and Carol hurries out. They exchange several lines of dialogue, but it all appears to be dubbed. During most of the dialogue, each character's mouth is not shown when they speak. However, the cadence of Katie's moving jaw can still be seen from behind, and appears to last longer than the audible speech. Additionally, Katie and Carol can each be heard to speak when it can be glimpsed that their mouths are not moving.
Factual error: In the last 2 episodes of series 2, when anyone uses a phone box it has the the BT Piper logo on the outside, which wasn't introduced until 1991 - six years after the series is set.
Pompeii's Gate to Hell - S4-E8
Factual error: This episode includes a segment about an abandoned dry dock in San Francisco. At one point, one of the commentators several times refers to the U.S.S. Ward as a "battleship," and marvels that it was built in 17 days. The Ward (DD-139) was a 1200-ton destroyer, not a battleship, and was launched after only 17 days, but then took another two months to complete. By way of comparison, the California (BB-44), an actual battleship of 32,000-tons built during the same time period, too nearly five years to complete.
Factual error: Johann Eck is dressed as a cardinal and Albrecht von Brandenburg addresses him as "Your Eminence" and kisses his ring. In reality, Eck was not a cardinal. Albrecht, however, was. It should be Eck showing deference to him, not vice versa. Albrecht was also only thirty, half the age of the actor playing him.
Factual error: When Detective Inspector Sara Lunt's photograph in uniform is shown on the TV news she is wearing a double row of silver lace below her hat badge. Only chief constables wear this insignia, well above the rank of inspector.
Episode #1.3 - S1-E3
Factual error: Billy is called up into a specific unit of the Royal Artillery. This didn't happen. He would first have been sent to a Royal Artillery training depot and only after training would he have been assigned to a unit.
Episode #1.2 - S1-E2
Factual error: The settlers prepare to burn Verity at the stake as a witch. Witches were never burned in England or her colonies; they were hanged.
Character mistake: One of the characters, Agent L, is usually talking to the kids via some gadget with bad audio. In The Golden Gauntlet, the first time she appears on the screen she misnames Agent J, calling him "Agent G." She then later in her speech calls him by his name correctly.
Continuity mistake: Near the end of the episode when Nico is burning the photo of her father, she burns it at the top left corner in a close-up shot. Then in the following shot the photo is suddenly burning at the top right corner instead.
Factual error: Two women come into town somewhere around San Luis Valley, Colorado with ring-necked Pheasants. The pheasants were brought into US a few times (East coast, CA) but really did not get established until late 1880s and in Colorado likely in the late 1890s (eastern and southwestern). The problem is it supposedly depicts the year 1880. They would more likely may have found some Gunnisons Sage-Grouse nearby or rabbits. (00:16:10)
Factual error: The Navy Seals call in air support and provide a fire mission to given coordinates. The targets are engaged with rockets and gatling/chain guns. The UH-60 Black Hawk is shown leaving after the air strike. This UH-60 however only had mini-guns in the doors. The type of UH-60 needed for this action would be the UH-60 DAP, which is configured as a gunship and has no troop carrying capacity. The DAP can carry chain guns, mini-guns, missiles and or rockets. (00:03:00 - 00:03:23)
Continuity mistake: Celeste and Madeline are in the car and greet Bonnie, who's hiking. In the immediate shot of the copilot mirror's reflection Bonnie is nowhere to be seen.
Factual error: ACC Pat Gallan wears the ribbon of the Queen Elizabeth II Diamond Jubilee Medal. The medal was issued in 2012. Her medals would be correct for 2017 when the series was made, but not 2007 when it is set.
Continuity mistake: During the death battle, Wolf grabs his opponent and the big sword is held down below waist level. The shot cuts and it's suddenly up, over his shoulders.
Episode #1.3 - S1-E3
Audio problem: Elaine refers to someone's "ChatsApp" account, but her lip movements show she is actually saying "WhatsApp." (00:13:55)
Factual error: The provincial police is always described as the Ontario Police Department (OPD) instead of the correct Ontario Provincial Police (OPP).
Boundaries - S4-E3
Continuity mistake: Alex and his mom are talking with Grandma about masturbation. Alex is in his school uniform shirt but for one shot he has a hoodie on, then in the next shot it's gone.
Continuity mistake: The way "Jack Griffin" is written on the board changes in various shots.