Maybe try adding an additional line of code that forces it to use the default but new font? It sounds to me it is trying to input text that is a string that doesn't actually match the font, even though typing it directly results in the correct Cyrillic.
This can happen when you cut and paste from other fonts I think?
It's weird that this code below actually works in Tier 1, but doesn't function in Tier 2 ;
SetPrintFont(0)
Print("Приветики")
Maybe it is a bug of some kind.
I can't seem to be able to change font colours of TrueType Fonts at the moment in Tier 1. Not sure what's up with that either.