Troubles with encoding in game output

Steps to reproduce:

1. Enable game output in launcher settings
2. Start Minecraft and switch to Russian language (Русский)
3. Join any singleplayer world and observe
   Optional: you can try another commands like /say and game output will show � instead of normal text

Expected result: Game output should say: username зашёл в игру
Actual result: Game output says: username ������������� � ����