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?
Continuity mistake: After accidentally setting of the Abomination alarm, Amity and Emira run over to see what's happening. However, Amity has her normal hair, when she is supposed have a bun. This is fixed in the next scene. (00:13:18)
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.
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)
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)
Remembrance - S1-E1
Character mistake: Picard and Data are playing poker at the beginning of the episode. Before the actual faces of the players are revealed, we are shown close-ups of their hands as they put down the chips for the bet. When Picard says his first line in the series it's "See", and it is literally true, because in the previous shot, Data put his 5 cards down on the table and face up. (00:00:50)
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.
Factual error: The show, which is set in California in 1947, mentions the gas chamber, lethal injection and the electric chair as methods of execution in the state. Two murderers are sentenced to death by lethal injection and one is depicted being instead executed in the electric chair, which the governor states has been brought out of retirement for the occasion. In fact, California adopted the gas chamber as its sole method of execution in 1937 (having previously used hanging). Lethal injection was not used in the United States at all until 1982 and not adopted in California until 1993 (becoming the prime method in 1996). California has never used the electric chair.
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 #1.2 - S1-E2
Continuity mistake: While riding to Tom's family's funeral, Tom and Steve ride in the back of the car in that order. However, when they get out of the car at the funeral, Tom sits by the door and gets out first, followed by Jess. (00:10:14 - 00:10:52)
Revealing mistake: After Claire gets out of jail, she goes to her brother Nate's house. Nate lets Claire stay there till she is back on her feet. Nate made room for Claire in the basement. But the blocks in the basement wall are stacked directly on top of each other, not staggered like they should be. Definitely just a prop wall.
Factual error: A British soldier in 1940 says he was educated at the University of Warwick. The university wasn't founded until 1965.
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)
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)
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)