Character mistake: When Beth and her mother discuss the agent's fee of 15%, Beth says it is $49.54. However the prize money was $500, the expenses were $172.30, which leaves them $327.70. 15% of $327.70 equals $49.16. (00:10:00)
Plot hole: If the Lady of the Lake walks every night to her room and kills those in her path, why didn't Flora and Miles' parents die in their room by the hands of the Lady in the Lake when they first moved in?
Opening Act - S1-E4
Factual error: At the beginning, the screen shows that the year is 1988 in Corpus Christi, TX, then the camera pans into Selena and her sister eating tacos when their friend Jake arrives wearing an Arizona Diamondbacks shirt. The Diamondbacks did not exist in 1988. Phoenix was awarded a Major League Baseball expansion team in 1995 and the Diamondbacks made their debut in 1998, 10 years after this scene takes place. (00:00:30)
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)
The Funeral - S1-E3
Deliberate mistake: Though it serves the drama and black comedy of the scene, it's highly unlikely a modern, let alone future broadcasting network would neglect the importance of delay (usually around 30 seconds) between recording and "live" broadcast. Specifically, to prevent unexpected gruesome incidents like the exploding head seen in this episode from making it to air.
Visible crew/equipment: The camera crew and camera can be seen in the far left user box during the virtual meeting on the laptop. (00:16:00)
Factual error: The communication delay for earth-moon communications is around 2.6 seconds. Yet Emma's daughter simply dials a cell phone and is connected to her Mom in space past the moon in less than that. The communication has no time lag. (00:18:45)
Plot hole: Dr. Adam Soong is initially presented as a discredited scientist, banned from the scientific community; he gets debarred and his funding revoked. And it's not an internal matter; he is publicly exposed for it. His daughter in episode 6 even finds out this information on Google. Several news articles call him "mad scientist" and such. However, this same person at the same time throughout the rest of the season has every bit of pull and influence, not just through undercover channels, but is treated with the utmost honor and deference by the NASA PR people at public events.
Character mistake: The FBI team responds to a murder crime scene. The victim is lying face down in the bed with blood everywhere. The team leader takes the victim's wrist with his bare ungloved hand. A trained FBI agent would never touch a murder victim without gloves - one to protect himself and two not to contaminate the crime scene. (00:10:00)
It's Good to Be Back on the Moon - S1-E9
Factual error: The Apollo 11 flag gets knocked over by the Chinese rover...but the flag was blown over by the Eagle's takeoff thrust, witnessed by Buzz Aldrin. This was confirmed years later by the Lunar Reconnaissance Orbiter, which showed shadows of the flags planted at all six Apollo landing sites, bar Apollo 11's. The other 5 were all planted further from their landing craft precisely for that reason. It's also widely assumed that the flags on the moon would have been bleached white by decades of unfiltered sunlight, not in good condition like the one shown.
Continuity mistake: Kurt is still recovering from the beating he took in the previous episode with bad cuts on his forehead, checks and temple area. They are red and impossible to miss while he is in the police station. The cuts have miraculously disappeared in the next scene when he goes to visit Mona.
Other mistake: At the end, when the reflection of burned Lucy still shows her beautiful, Dracula's reflection shows him as he is seen; not old and ugly as in his usual mirror reflections.
Episode #1.6 - S1-E6
Continuity mistake: In the flashback of the dance instructor suffering a miscarriage, she opens a drawer before dropping to the ground. The drawer is still open when she starts feeling her uterus, but when she attempts to stand, the drawer is suddenly closed. (00:11:39)
Facing Fear - S3-E4
Factual error: The teams are at a US Coast Guard base. Two coasties are introduced. One as a chief (correct) and one as a "Captain." He is not a Captain, he is a Lieutenant. The USCG uses naval ranks, so the person with the two bars is a Lieutenant. A Captain is three pay grades above this, and uses eagles as insignia.
Factual error: A man enters a bank and begins firing his Glock 9mm pistol. A few of the men he shoots, jump up in the air after the rounds impact their bodies. Bullets hitting a body will never make it jump, or fly in the air. (00:00:01 - 00:01:46)
Factual error: Emily is in Paris when her boyfriend calls from Chicago and wakes her. She asks the time which he says is 7pm, and she says 3am in Paris, which cannot be. Central European Time is 6 hours ahead of NY and 7 from Chicago. 7 pm in Chicago would be 2 AM in Paris.
Continuity mistake: When Gi-do is checking himself into the hospital, he flips up the sunglasses he is wearing. The shot then cuts to Haeng-ja whispering something to him, and we can see Gi-do's right hand raised to be level with his head. When the shot cuts back to Gi-do, his right hand is suddenly lowered. (00:31:02)
Revealing mistake: There are bullets placed on the counter, the one casing has a hole in it from being drilled to show it's a dummy round and there's no gunpowder in it. (00:14:45 - 00:15:20)
In Dreams Begin Responsibilities - S1-E1
Continuity mistake: She is on an elevator wearing her uniform. The uniform collar does not show her Chief of Police stars on it but when she walks off the elevator down the hall into her office less than 10 seconds later, the stars reappear on her collar.
Factual error: In Massachusetts, Atticus, Leti and George are attacked by the local sheriff and his deputies, who are patrolling the county roads. In Massachusetts, sheriffs run the county jails, but they do not (and did not) handle routine policing, which is the responsibility only of municipal police departments.