New fonts are unable to display russian characters. The game is not very capable of handling frequent language switches, I am afraid. For the rest of the world, it's solved with a respawn. Companions however are "saved" in your game file, so their name is never refreshed, no matter how much you sleep.
I'll add a quick fix for this: whenever you enter an area (or load a game), party member names will be re-generated with current language settings.