Hey, thanks for the detailed bug report. I can see the screenshot with garbled Korean characters, so the issue is clear.
This is a known bug that affects CJK languages like Korean, Japanese, and Thai when using Composer models. We’ve gotten a few similar reports over the last few days:
- Composer 2 Fast: Korean UTF-8 broken in chat and agent edits (Composer 2 OK)
- Thank you for Cursor - Japanese text gets garbled in Composer 2 Fast, but renders correctly in regular Composer and GPT
- Unicode (Thai) garbled in Composer 1.5/2 and sometimes on Auto
I’ve passed this to the team along with your Request IDs. There’s no ETA for a fix yet, but more reports help us prioritize it.
As a workaround, you already noticed GPT-5.4 and Gemini 3.1 Pro work correctly. Until there’s a fix, I’d recommend using those models for tasks with Korean text.
I’ll update the thread when I have more info.