In my files I tagged the main performers of a Melodiya Kozlovsky Requiem in Latin text.
However, most of them have been mapped to their Cyrilic equivalents, whilst others have not.
This is completely opposite to roon’s normal behaviour which is in general to default to American equivalents (although this general behaviour is also not consistent, for example Berliner Philharmoniker maps to Berlin Philharmonic Orchestra but Vienna Philharmonic maps to Weiner Philharmoniker).
I have noticed this a few times recently, not just with Russian composers but also Greek. Is there some kind of sanity check can be done depending on the language of the roon you are using? I don’t know if there are Russian or Greek localisations of roon in which case it probably does make sense to map latin to cyrillic equivalents if they are available.