[BUG] 返答の文章が2回重複して表示される

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?

The assistant's response is sometimes displayed twice in a row — the exact same paragraph appears duplicated immediately after itself. This looks like a rendering/display issue, not the model generating the text twice, since the two copies are word-for-word identical.

What Should Happen?

Each assistant response should be displayed only once.

Error Messages/Logs

Steps to Reproduce

1. Use Claude Code Desktop App (Mac) normally in conversation
2. Occasionally (not every response), the assistant's reply text renders twice in a row, identical word-for-word
3. No specific action seems to trigger it — happens intermittently during normal use

See attached screenshot for an example.

Claude Model

None

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

Claude Code Desktop App (Mac) — version unknown (not the CLI, no claude --version available)

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

Using Claude Code Desktop App for Mac (not CLI in terminal). macOS 26.5.2.

<img width="346" height="575" alt="Image" src="https://github.com/user-attachments/assets/bd79eceb-a979-408d-b861-043031b79fed" />