[BUG] The new renderer causes garbled text sometimes

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?

From time to time, the new full-screen renderer under Windows Terminal causes whitespace to be rendered as garbled text:

<img width="1710" height="213" alt="Image" src="https://github.com/user-attachments/assets/b7dfa10d-1c9e-457f-81eb-6fe4f8d34974" />

Also, I've noticed that sometimes the lower portion of the screen fails to redraw. This typically happens when the workflow pane is displayed and the user browser through agents. In that case, part of the screen is just black. The affected part is the bottom status and agent pane.

What Should Happen?

Clean display without extra characters.

Error Messages/Logs

N/A

Steps to Reproduce

No particular repro. The problem just appears in a running session without visible external influence.

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.234

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

_No response_