Unicode (Thai) garbled in Composer 1.5/2 and sometimes on Auto

Support Bug Reports
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1

Where does the bug appear (feature/product)?

Cursor IDE

Describe the Bug

After the most recent Cursor update, assistant replies that include Thai (and possibly other non‑ASCII Unicode) are often corrupted in the UI: characters appear as replacement glyphs (), split or wrong vowels/tone marks, or other mojibake. The same text is correct when viewed in editor tabs and in UTF‑8 project files, so this looks like a rendering / encoding pipeline issue in the product UI, not bad file content.

Pattern: The problem is reproducible every time when using Composer 1.5 and Composer 2. When using Auto (model routing), it happens only sometimes (intermittent).

Build: Cursor 3.0.16 (VS Code 1.105.1), Windows x64 10.0.26200, Stable, Electron 39.8.1 / Chromium 142.0.7444.265 (commit 475871d112608994deb2e3065dfb7c6b0baa0c50, dated 2026-04-09).

Steps to Reproduce

  • Install/update to Cursor 3.0.16 on Windows 10 (build 10.0.26200).
  • Open a UTF‑8 project that contains Thai text (e.g. Markdown docs).
  • Open Composer and set model to Composer 1.5 or Composer 2 (not Auto).
  • Ask the assistant to explain, quote, or summarize in Thai (or to discuss Thai content from the repo).
  • Observe the Composer / Chat output: Thai is often garbled (`` or broken syllables).
  • Compare: Open the same passage in an editor tab — text is correct there.
  • (Optional) Repeat with Auto: note that corruption is intermittent rather than every time.

Expected Behavior

Assistant output should preserve valid UTF‑8 end‑to‑end: Thai (and other Unicode) in Chat / Composer should match what appears in the editor and standard Windows apps—no `` replacements or broken combining characters.

Screenshots / Screen Recordings

2026-04-10 171802.png
2026-04-10 171802.png1897×1052 226 KB

Operating System

Windows 10/11

Version Information

Version: 3.0.16 (user setup)
VSCode Version: 1.105.1
Commit: 475871d112608994deb2e3065dfb7c6b0baa0c50
Date: 2026-04-09T05:33:51.767Z
Layout: editor
Build Type: Stable
Release Track: Default
Electron: 39.8.1
Chromium: 142.0.7444.265
Node.js: 22.22.1
V8: 14.2.231.22-electron.0
OS: Windows_NT x64 10.0.26200

For AI issues: which model did you use?

Auto, Composor 1.5, 2

Does this stop you from using Cursor

No - Cursor works, but with this issue

5

Hey, thanks for the detailed report and the screenshot. I can see the garbled Thai text in the chat output.

This is a known issue with Composer 1.5/2 models. They don’t handle non-ASCII Unicode correctly (Thai, Korean, Vietnamese, etc.). We got similar reports today from users in other languages:

The team is aware of the issue. We don’t have an exact ETA yet, but your report helps with prioritization.

As a workaround, try switching to a different model (like Claude or GPT) instead of Composer 1.5/2 when you work with Thai text. In Auto, it happens less often since routing doesn’t always pick a Composer model.

If you can, please send the Request ID (top right of the chat > Copy Request ID) from one of the broken messages. That’ll help with extra tracing.

8

Hey @Ariya_Owam-aram,
Just checking in — are you still experiencing the garbled Thai text issue in Composer? Recent updates should have improved this. If you’re still seeing it after updating to the latest version, let me know and I’ll dig deeper.