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.
Chernobyl (2019)
1 other mistake in Open Wide, O Earth
Starring: Jared Harris, Jessie Buckley, Paul Ritter
Genres: Drama
The Happiness of All Mankind - S1-E4
Continuity mistake: When Legasov proposes to use Bio-robots, Scherbina pours 2 glasses of vodka. One glass is about 80% full, another 60%. However, when glasses are placed on the table, they appear to be both filled to 80%. (00:39:27)
Trivia: The musical score was based on ambient audio samples taken from a decommissioned Lithuanian power plant where the series was filmed.