Text overlaps and becomes unreadable when using GPT-5.6 Terra

What version of the Codex App are you using (From “About Codex” dialog)?

26.707.3748.0

What subscription do you have?

ChatGPT Plus

What platform is your computer?

Microsoft Windows 11 Pro 25H2, build 26200.8737, x64

What issue are you seeing?

When using GPT-5.6 Terra in the Codex desktop application, the response text is rendered incorrectly.

Multiple lines and text blocks overlap each other, making the response partially or completely unreadable. The problem appears directly inside the Codex interface after the response is generated.

The issue is visible in the attached screenshot.

<img width="458" height="408" alt="Image" src="https://github.com/user-attachments/assets/239d1c78-b707-4dd2-90db-0091709e8e8e" />

What steps can reproduce the bug?

1. Open the Codex desktop application.
2. Start a new session or open an existing session.
3. Select GPT-5.6 Terra.
4. Submit a prompt that generates a multi-line response.
5. Wait for the response to finish rendering.
6. Observe that lines and text blocks overlap each other.

The problem is reproducible with different prompts.

What is the expected behavior?

The generated response should be displayed normally, with every line and text block positioned separately and fully readable.

No text should overlap, merge, or cover other parts of the response.

Additional information

Codex app version: 26.707.3748.0
Subscription: ChatGPT Plus
Operating system: Microsoft Windows 11 Pro 25H2
Windows build: 26200.8737
Architecture: x64
Display resolution: 1920x1200
Display scaling: 100%
System language: ru-RU
Computer: Lenovo 21JN21JN00

The issue occurs specifically when using GPT-5.6 Terra. Changing the prompt does not prevent the problem.