No seriously, I saw many cases with BBC, like when they conduct an interview about political situation with a person pretending to have telepathic abilities.

In this particular case, google translate learns from texts existing in both english and russian (for example newspapers which are published in two languages, etc)

I doubt there are newspapers or other texts where russian article saying "Russia" is translated to english with "Mordor".

It's much more likely a kind of flashmob by ukrainan users who submitted manual corrections to google translate.