[macOS] Review only shows the latest turn instead of the selected turn's changes

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

26.825.51511

What subscription do you have?

ChatGPT Pro

What platform is your computer?

25.4.0 arm64 arm

What issue are you seeing?

Describe the bug

In Codex Desktop on macOS, reviewing changes from a multi-turn session only shows the diff from the latest turn/worktree state.

Previously, selecting an earlier turn allowed me to review the changes introduced in that specific turn. Now, regardless of which turn I select, the review panel displays only the latest changes.

This makes it difficult to review or verify incremental changes across a multi-turn coding session.

Steps to reproduce

1. Open a repository in Codex Desktop on macOS.
2. Ask Codex to make a change.
3. Ask Codex to make another change in a later turn.
4. Open the review/diff view for the earlier turn.
5. Compare the displayed diff with the changes introduced in that turn.

Expected behavior

The review view should show the diff associated with the selected turn.

Actual behavior

The review view shows the latest worktree diff instead of the selected turn's diff.

Environment

• OS: macOS
• App: Codex Desktop
• Regression: This worked previously, but now only the latest turn can be reviewed.

Additional context

This may be related to historical-turn review state or merge-base/worktree diff caching. Similar behavior may be related to #40830 and #35667, but this report focuses on the regression where selecting different turns produces the same latest diff.

What steps can reproduce the bug?

1. Open a repository in Codex Desktop on macOS.
2. Ask Codex to make a change.
3. In a later turn, ask Codex to make another change.
4. Open the Review view for the earlier turn.
5. Select the earlier turn's changed files.
6. Observe that the review shows the latest worktree diff instead of the selected turn's diff.

What is the expected behavior?

The Review view should show only the changes introduced by the selected turn.

Additional information

No response

Reproduce the issue in Codex Desktop on macOS using the listed multi-turn steps, then inspect the Review/diff view when an earlier turn is selected. Compare the displayed diff with the changes introduced by that turn and check the historical-turn review state or merge-base/worktree diff behavior mentioned in the report. Done means each selected turn shows only its own changes rather than the latest worktree diff.