Windows 10 Pro, 64-bit; TTS version 11.0.1; Atom mode version 11.0.2

Often JSON.decode(unicode_string) replace some of russian letters to �.
I have work-around: save string as array of bytes.
Code:
function stringToBytes(str)
    local result = {}
    for i = 1, #str do
        result[i] = string.unicode(str, i)
    end
    return result
end

function bytesToString(bytes)
    local str = ''
    for i, char_code in ipairs(bytes) do
        str = str..string.char(char_code)
    end
    return str
end
But it still work-around, not fix.
I hope developers help me and other modecreators, thank you for attention.