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?
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)
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.
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)
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.
Continuity mistake: When Jonah confronts Meyer after the death of the surgeon, Meyer's holding a drink in his left hand as he turns to face Jonah. The shot changes angle and the drink is suddenly in his right. (00:48:40)
Continuity mistake: The three friends finally meet in person after all the texting. Karube brings a cigarette to his mouth when Chota asks "Where to?", but in the next shot his hand is lower. (00:07:15)
Angel of Mercy: Part Two - S1-E4
Character mistake: When Lenore Osgood is speaking on the phone with Charles Wainwright about killing Dr. Hanover, she mispronounces "Larynx" as "Lar-nix."
Continuity mistake: Throughout the series, the Barbers pull their cars straight up their driveway. But the cars are nearly always shown coming back down the driveway driving forward.
Other mistake: Jesus leaves his home with a double barrel break-action shotgun and an ammunition belt holding extra shot-shells. In the next scene Jesus is walking in the street with the shotgun and no ammunition belt, it magically vanished. The shotgun only has a capacity for 2 shot-shells, then it needs to be reloaded, or it can be reloaded after one is only fired, that procedure is called a top-off. He fires 1 round at the mayor and two inside Elena's home which makes three. He never reloads. (00:32:50 - 00:34:40)