[BUG] Multiple blank spaces are automatically inserted during text input

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?

While typing text in Claude Code, the input field intermittently inserts multiple blank spaces automatically.

These extra spaces appear without intentional input and can significantly disrupt text formatting and editing. The issue makes it difficult to write or edit code and plain text accurately.

What Should Happen?

<img width="1574" height="111" alt="Image" src="https://github.com/user-attachments/assets/fc1c8e20-9d44-48aa-83b0-3ec12f565373" />

Error Messages/Logs

Steps to Reproduce

1. Open Claude Code
2. Click on the text input field
3. Start typing any text

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

v2.0.73

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

This appears to be a regression. Version 2.0.70 behaves correctly, while newer versions exhibit the unintended whitespace insertion issue.