[BUG] Vowels missing in Claude's screen output.

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?

Claude asked me what option I would like it to take, nothing unusual there. Except all the vowels had been stripped from the output. There were spaces where the vowels should have been. Never seen anything like it previously, and it did not reappear in the limited interactions following it. Claude had no idea it had happened. Obviously had to terminate session and can no longer trust Claude until this issue has been sorted out.

What Should Happen?

The text should display normally.

Error Messages/Logs

No error messages. Claude had no idea it had happened.

Steps to Reproduce

No idea how to reproduce it, it was just a Claude screen interaction.

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.34

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

_No response_