Normally I would find these kinds of mistakes unforgivable, but Chernobyl also gets a great many facts right, not the least of which is the human suffering of a terrible nuclear accident. Some scenes might be too graphic for people. Chernobyl does not shy away from the more unpleasant aspects of this disaster.
Early on in the miniseries, many of the nuclear workers and scientists can't fathom how such an accident could happen. The show keeps us in suspense by saving the explanation for last. It was a combination of bad design and poor training leading to incompetent nuclear workers.