Other mistake: When Harold goes to kill his father, we see his dad on the seat moving each time we hear the hammer, but if you look at his head, you don't see anyone hitting him at all.
What They Saw in Southie High - S1-E2
Other mistake: Agent Rohr asks who the cold case is related to. A dossier is given to him and the front cover contains a photograph and the name "Kanicki, K". Agent Rohr says "Kelly Kanicki" but there was no indication of the full name, just the initial. (00:08:30 - 00:09:00)
Who Are You? - S1-E4
Other mistake: Magpie is surprised by the guard at the beginning of the episode; the guard is running in the room, hand going for the gun. After a cut to her with close-up on her elaborate fetching of the bombs with her awkward nails, the man is standing still, hand down his leg, only then going for the weapon. Two bombs fall at his feet, one per foot, touching the feet directly. Obviously he just looks at what they are instead of jumping back, and they explode in a single mushroom cloud CGI explosion, to his left. (00:01:10)
No One's Gonna Harm You, Not While I'm Around - S1-E5
Other mistake: When Mitch is getting escorted out of the building, he gets in an elevator. Just as the elevator doors begin to close, Bradley Jackson jumps in the elevator to have a conversation with Mitch. As she does, the elevator doors continue to close, even though she has jumped right in front of them while they are closing. Elevator doors have a safety sensor, and the safety sensor would have been triggered by Bradley jumping in the elevator as the doors are closing, and the doors would have reopened.
Other mistake: The extent to which the classmates wrapped Miles in cellophane with his hands folded in front of his groin would make it difficult, if not impossible, for Miles to get out of the lake alive on his own. Miles did not drown... or suffer any injuries.
Other mistake: Legasov is told that a 30km zone will be evacuated, shown as an ill-founded cabinet decision. Legasov himself proposes a 200km zone. At the end of the episode, Legasov appeals to Gorbachev (General Secretary) and asks him to evacuate 2600 square kilometers. It's easy to check that this is a 29km radius circle, nothing like the 200km he proposed.
Episode #1.1 - S1-E1
Other mistake: When Tony walks by the school there's a girl in a blue dress with a hula hoop that can't stop staring at the camera.