Hey, thanks for the detailed report. This is a known issue. Auto mode routes requests to the Composer 2 Fast model, which incorrectly handles CJK characters like Korean, Japanese, Chinese, and so on.
The team is aware, and we’ve gotten dozens of similar reports over the last few days. For now, the only workaround is the one you already found. Manually select a specific model like Claude Sonnet 4.6 or GPT instead of Auto.
Related threads for context:
- Encoding issues in Auto Mode (Korean text broken)
- [BUG]Korean characters broken (encoding issue) in Composer/Agent
- Composer 2 Fast: Korean UTF-8 broken in chat and agent edits (Composer 2 OK)
Let me know if you run into anything else.