[BUG] Voice mode mishandles cursor position

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?

In addition to other related voice mode issues already reported, I am having the separate issue where at some points while I am speaking, the cursor jumps back from the end of the text to about a dozen characters to the left; at this point, transcription stops even if I continue speaking.

What Should Happen?

Voice mode should work the same as it did before. This is a regression.

What I want is to hold the spacebar and speak and it gets transcribed. And the cursor is always at the end of the transcribed text, both during speech and after.

Error Messages/Logs

Steps to Reproduce

1. Get voice mode to transcribe at all (sometimes requires restarting the CLI, as per other bug reports)
2. Use voice mode. Don't write entire messages in one activation of the mode. Instead, speak a few sentences, release spacebar, let the text go normal white. Then press and hold spacebar again. Continue speaking. Hopefully the issue will show up.

Claude Model

Sonnet (default)

Is this a regression?

Yes, this worked in a previous version

Last Working Version

I believe 2.1.83, as this regression is very recent.

Claude Code Version

2.1.84 (Claude Code)

Platform

Anthropic API

Operating System

Ubuntu/Debian Linux

Terminal/Shell

Other

Additional Information

<img width="390" height="54" alt="Image" src="https://github.com/user-attachments/assets/4cf4d39f-430b-4762-a6bf-1fee14105213" />

The cursor moved to that position by itself during use of voice mode.