Codex app: Last Turn review renders the same newly added file twice

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

26.901.51231 (build 8109), read from the installed app's Info.plist. Bundle identifier: com.openai.codex.

What subscription do you have?

Not collected.

What platform is your computer?

macOS 26.6.2 (25G83)

uname -mprs: Darwin 25.6.0 arm64 arm

What issue are you seeing?

The desktop review panel's Last Turn view displays the same newly added test file twice as consecutive file diff sections.

A screenshot from the affected session shows:

• The first section's header contains the file's full repository-relative path and +94 −0.
• That section reaches the end of the added file at line 94.
• Immediately below it, a second file section repeats the exact same full path and +94 −0, restarting the added content at line 1.
• The overall Last Turn header shows +124 −4.

This is not two different files with the same basename: the full paths displayed in the two headers are identical. Filesystem inspection and git status --short confirm a single new, untracked file at that path. A separate modified test file has a different basename and path.

What steps can reproduce the bug?

Observed workflow in a managed Git worktree:

1. Have Codex modify existing source files and add a new TypeScript React test file during a task.
2. Open the review panel and select Last Turn.
3. Scroll through the newly added file to its final line.
4. Observe another full addition section for the same path immediately below it.

The exact trigger and reproduction frequency are not yet isolated. This report describes the observed session, not a verified minimal reproducer. Whether other diff views are affected has not been checked.

What is the expected behavior?

The Last Turn view should display a single file section per repository-relative path, with that turn's changes consolidated. Reaching the end of a newly added file should not lead to the same file's addition being rendered again.

Additional information

The screenshot was inspected to verify the repeated headers and line-number restart. Repository paths, source code, session contents, and the screenshot itself are omitted from this public report because they belong to a private project. No duplicate source file was found, and the root cause in the review UI or diff aggregation is unknown.

Start at the Codex app's Last Turn review panel and trace how changes for newly added files are aggregated and rendered; the report names no source file or test entry point. Reproduce in a managed worktree with an added TypeScript React test file, then verify that each repository-relative path appears in one consolidated section.