[BUG] Automatically crashes when updating related Markdown documents

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

When I enter the command 'Update relevant documentation based on the changes above,' the application crashes while processing the CHANGELOG.md file.

The error message is as follows:

● Read(docs\CHANGELOG.md)
  ⎿  Read 10 lines

  Update(docs\CHANGELOG.md)

* Deliberating… (esc to interrupt · 1m 47s · ↓ 813 tokens · thinking)

──────────────────────────────────────────────────────────────────────────────────────────────────────
> 
──────────────────────────────────────────────────────────────────────────────────────────────────────
  ⏵⏵ accept edits on (shift+tab to cycle)

thread '<unnamed>' (29708) panicked at /rustc/ed61e7d7e242494fb7057f2657300d9e77bb4fcb\library\core\src\str\mod.rs:833:21:
byte index 8 is not a char boundary; it is inside '化' (bytes 6..9) of `能优化`
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

What Should Happen?

Don't crash; edit Markdown files normally.

Error Messages/Logs

Steps to Reproduce

Enter 'Update relevant documentation based on the changes above,'

Crash Happen:

● Read(docs\CHANGELOG.md)
  ⎿  Read 10 lines

  Update(docs\CHANGELOG.md)

* Deliberating… (esc to interrupt · 1m 47s · ↓ 813 tokens · thinking)

──────────────────────────────────────────────────────────────────────────────────────────────────────
> 
──────────────────────────────────────────────────────────────────────────────────────────────────────
  ⏵⏵ accept edits on (shift+tab to cycle)

thread '<unnamed>' (29708) panicked at /rustc/ed61e7d7e242494fb7057f2657300d9e77bb4fcb\library\core\src\str\mod.rs:833:21:
byte index 8 is not a char boundary; it is inside '化' (bytes 6..9) of `能优化`
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.1

Platform

Google Vertex AI

Operating System

Windows

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_