Chernobyl documentary footage vs. scenes from the show

HBO's Chernobyl was widely praised for its realistic depiction of the disaster and of the late Soviet Union itself: so meticulous that its mistakes and simplifications stood out in uncanny relief to those who were there.

In this video, Thomas Flight compares footage from the show with the documentary footage it was based upon.

I'm curious about why the text on the scene below, derived from Soviet TV broadcast announcing the disaster, differs from the original. Did HBO use a different source, or did they change it themselves some reason? (Novosti) means "NEWS" and was then (and now) the name of the official news agency, while (Vremya) means "TIME" and is apparently the name of the evening news show.

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