It's algorithm is probably associating words or ideas with equivalent but not identical best match in English - if you translate First Patronymic of some famous dude (famous enough that the bingbot has a lot of Russian and English text about them to learn from) it'll spit out the English First Last - as the patronymic will rarely be used in English articles about them. In that way First-Patronymic serves as sort of a dual-index on the Russian half of the Russian-English translation. Just a guess