[macOS] Codex in-app side browser renders pages as a repeated tiled grid

Summary

The Codex in-app side browser on macOS renders some pages as a repeated tiled grid. The selected tab identity, URL, title, and DOM are correct, but the visible WebView and fresh screenshots show the page duplicated across a large canvas. This prevents reliable visible browser work.

Environment

• ChatGPT desktop: 26.707.72221
• Codex Framework: 150.0.7871.115
• macOS: 26.5.2 (25F84)
• Affected Codex task ID: 019f68cc-229f-7c81-a1d6-74e506d99ef8

Steps to reproduce

1. Open the Codex in-app side browser.
2. Create a fresh visible tab owned by the current task.
3. Navigate to https://royalsmells.com/ or the GitHub Codex issue form.
4. Confirm the selected tab ID matches the controlled tab ID.
5. Confirm that the URL, title, and DOM load normally.
6. Inspect the visible WebView or take a fresh screenshot.

Actual behavior

The rendered page is repeated horizontally and vertically as a tiled grid. Repeating the test once in a second fresh tab produces the same result.

Expected behavior

The side browser should render one correctly sized page matching the visible viewport.

Troubleshooting already completed

• Backed up and reset GPUPersistentCache, GraphiteDawnCache, and ShaderCache.
• Backed up and reset the isolated in-app browser profile.
• Restarted ChatGPT/Codex and retested with fresh tabs.
• Verified selected-tab identity, URL/title, non-empty DOM, and fresh screenshots.
• Attempted a temporary software-rendering relaunch. Chromium GPU-disabling flags were not retained by the main process, and the GPU service continued running.
• A simple Google page rendered normally in one control test, while Royal Smells and the GitHub Codex issue form consistently reproduced the tiling.
• No cookies, profiles, passwords, or live service settings were changed.

Diagnostics

App logs are available locally under ~/Library/Logs/com.openai.codex/. Sanitized diagnostics can be supplied on request.