Codex Desktop macOS Intel does not persist approval_policy / sandbox settings from UI

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

26.513.31313 (2867)

What subscription do you have?

Plus

What platform is your computer?

Darwin 21.6.0 x86_64 i386

What issue are you seeing?

Codex Desktop on macOS Intel reads ~/.codex/config.toml correctly, but does not persist Approval Policy and Sandbox settings when changed from the UI.
The user interface displays the message "Unable to save" and the field value does not change.

Manual edit works correctly.

For example, if I manually set:
approval_policy = "on-request"
sandbox_mode = "workspace-write"
After I reopen the app I see the settings changed.

What steps can reproduce the bug?

Open Codex Desktop on macOS Intel.
Set Approval Policy / Sandbox settings from the UI.
Check ~/.codex/config.toml.

What is the expected behavior?

The UI should write valid config values, for example:

approval_policy = "on-request"
sandbox_mode = "workspace-write"

Additional information

This does not appear to be a filesystem permission issue, because manual edits to ~/.codex/config.toml work and are correctly reflected in the UI.