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 - chronological order
Starring: Jared Harris, Jessie Buckley, Paul Ritter
Genres: Drama
The Happiness of All Mankind - S1-E4
Factual error: When Bachu talks to Pavel during their lunch, two bottles of vodka are visible. Top of the bottle should read: RUSSKAYA, however, it's misspelled and reads "RUSSKAVA." Other issue with those bottles - in the center it should read in Russian "Русская Водка", however, although "Водка" spelled correctly, the "Русская" is misspelled and ends on "ерская", which is incorrect. (00:30:26)
Trivia: The musical score was based on ambient audio samples taken from a decommissioned Lithuanian power plant where the series was filmed.