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: 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)
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)
Episode #1.1 - S1-E1
Continuity mistake: After Weol-ju has hanged herself on the tree and the spirits begin to emerge from it, in one shot, her hair is shown behind her head, but in another shot, some of her hair can be seen going over her shoulder. (00:15:18)
Continuity mistake: When Eden confronts Kinsey by the lockers, as the angle changes so does Kinsey's arm. In some shots, she has her arms crossed and the locker door is closed, in some shots she has one arm up, holding the (open) locker door.
Continuity mistake: An employee is asked to leave the computer lab, he actually exits it twice. (00:11:15)