It's not the question of grammar but semantics. Wrong grammar is when you put the verb before the subject in English. The grammar does not decide whether you

It's not the question of grammar but semantics. Wrong grammar is when you put the verb before the subject in English. The grammar does not decide whether you say "on a call" or "in a call". Wrong grammar would be if you used an incorrect case after the preposition, but the very choice of it involves the speaker and what semantics or meaning is meant by them. Okay - you would find "NA" in the Russian corpus from the 17th century - but it is totally meaningless because East Ukraine was annexed in 17th century by Russia. I would have bet that this particular preposition was preferred. I don't think any books on Russian grammar recommend a specific preposition - most likely you meant some stylistic compendium, but the style is something more subjective and even political in nature, isn't it? In a nutshell, it's not a grammatical or historical thing, it's just shameless linguistical colonialism in its purest form.