Codex “Review” panel intermittently loses diff list (“No diff data”) and “Undo” does nothing

What version of Codex is running?

0.4.69

What subscription do you have?

ChatGPT Plus

Which model were you using?

gpt-5.2-codex

What platform is your computer?

Windows 10 x64 (desktop)

What terminal emulator and version are you using (if applicable)?

VS Code integrated terminal (PowerShell) — version 1.108.2

What issue are you seeing?

After Codex edits one or more files, clicking “Review” to open the changed-files list is unreliable. Most of the time, the file list appears for ~1 second and then immediately disappears and the Codex Diff view shows “No diff data”. In the same state, clicking “Undo” does not revert any changes. The behavior is erratic: I often need to click Review/try multiple times (4–5 attempts) until the diff list finally loads and stays visible. This suggests the diff/undo state is being cleared or failing to load intermittently.

What steps can reproduce the bug?

1. In VS Code with the Codex extension enabled, open any workspace/repo.
2. Use Codex to apply a change to a file (so the Codex UI shows “1 file changed” or similar).
3. Click the “Review” button in the Codex panel.
4. Observe: the changed-files list flashes briefly and then the Codex Diff tab shows “No diff data”.
5. Click “Undo” in the Codex panel.
6. Observe: nothing is undone (the modified file remains modified).
7. Repeat steps 3–6 a few times; eventually Review may succeed and the diff list stays visible.

What is the expected behavior?

When I click Review, the list of changed files and diffs should reliably load and remain visible until I close it or change selection. “Undo” should reliably revert Codex-applied edits (restoring the file(s) to the prior state), regardless of how quickly Review is opened.

Additional information

• Frequency: high / intermittent (fails most attempts; usually succeeds only after several retries).
• Suspected relationship: Review failing to load diff data and Undo doing nothing appear related (likely the same underlying diff/state tracking issue).

Attachments: screenshots showing “No diff data” and the Review/Undo UI state.

<img width="370" height="284" alt="Image" src="https://github.com/user-attachments/assets/d5efb754-979f-451d-9a9a-2fa0b851e379" />

<img width="1553" height="957" alt="Image" src="https://github.com/user-attachments/assets/3808a4e9-2bea-4c1f-9069-4c1c07a1b758" />