Problem with Cyrilic codepage when in Condensed mode

[ghost]

Test printer Birch CP-Q3, code page 1251-Cyrilic(Windows) - printing in Normal mode is totally OK but any attempt to print Cyrilic characters in condensed mode, results with blank spaces or question marks instead of wanted words. Following code:
Vip.Printer.Printer prn = new Vip.Printer.Printer("CP-Q3", Vip.Printer.Enums.PrinterType.Epson, Encoding.GetEncoding("Windows-1251"));
prn.CondensedMode(Vip.Printer.Enums.PrinterModeState.On);
prn.WriteLine("=====ОВО ЈЕ ЋИРИЛИЦА====="); // This means "THIS IS CYRILIC"
prn.CondensedMode(Vip.Printer.Enums.PrinterModeState.Off);
is resulting with: "===== =====" // Empty space in the middle is actually 15 blanks wide (length of my phrase) - GitHub shortens it when message is saved.
Than tried CondensedMode with string constructor, as well as Font method - both ways give question marks for each character wanted to print. Like:
prn.CondensedMode("=====ОВО ЈЕ ЋИРИЛИЦА=====");
prints: "=====???????????????====="); // 15 question marks
Tested it for few hours and concluded that problem emerges with characters/code pages other than IBM Standard, like 1251-Cyrilic or 1250-Central Europian (characters like ŠšĐđŽžČčĆć), both lower or upper case.
Any idea how to overcome this issue? Is it because of driver or some strange hardware fault?