[BUG] Claude responds again to a /btw question every time detailed transcript ( Ctrl+ o ) is toggled

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?

Every time I toggle detailed transcript, claude response again to the previous /btw question. It doesn't look like a UI quirk rendering the answer again as I see "Answering..." blinking for sometime before claude responds and it seems to make an API call.

<img width="1674" height="242" alt="Image" src="https://github.com/user-attachments/assets/1a1c0f1b-adeb-478d-b302-243e831cfde9" />

What Should Happen?

The previous answer should just be in the chat history. There shouldn't be any new responses to an old /btw question.

Error Messages/Logs

Steps to Reproduce

1. Ask a /btw question to claude code in an existing session with some previous chats0
2. toggle detailed transcript with ctrl+o repeatedly.
3. see that claude is responding again and again to the previous question.

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.156 (Claude Code)

Platform

Google Vertex AI

Operating System

Other Linux

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_