[macOS][Desktop Chat] GPT-6 Pro disappears from model picker after switching conversations

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

Latest version immediately after an update (reported); exact version/build not yet recorded.

What subscription do you have?

Not specified in this report; GPT-6 Pro / GPT-6 options are visible for the same account immediately after relaunch.

What platform is your computer?

macOS; exact OS version not yet recorded.

What issue are you seeing?

Summary

In the macOS desktop app’s Chat surface (Codex Desktop / ChatGPT Desktop), GPT-6 Pro and GPT-6 are visible immediately after updating and restarting the app. Switching to another conversation and then returning to the original conversation causes all GPT-6 options to disappear from the model picker. Fully quitting and relaunching the app restores them.

Actual

After switching away and back, all GPT-6 options disappear. The picker shows only:

• Latest (displayed as “最新” in the Chinese UI)
• GPT-5.6 Sol
• GPT-5.5

This report describes user-observed behavior; no independent runtime reproduction or diagnostic trace is attached.

What steps can reproduce the bug?

1. Update the desktop app and restart it.
2. Open a conversation in Chat mode (conversation A).
3. Open the model picker and observe that GPT-6 Pro / GPT-6 options are visible.
4. Switch to a different conversation (conversation B).
5. Switch back to conversation A.
6. Open the model picker again: all GPT-6 options are now missing.
7. Fully quit the desktop app (Cmd+Q), relaunch it, and inspect the Chat model picker: GPT-6 options reappear.

What is the expected behavior?

Switching between conversations should preserve the available model options for the same signed-in account. GPT-6 Pro / GPT-6 should remain visible and selectable when available to that account, without requiring an app restart.

Additional information

Important observations

• The same account already shows GPT-6 options before the conversation switch and again after relaunch; this is not a report of never having seen those options.
• The visible change happens within a single app session after navigating away from and back to a conversation.
• Fully quitting and restarting restores the options without changing accounts.
• These observations establish inconsistent picker visibility, not a verified backend entitlement diagnosis or confirmation of which model serves a request.

Suspected area (unverified)

Conversation remount or model-catalog / entitlement reconciliation may be involved. One hypothesis is that returning to an existing conversation replaces or filters the initially available model catalog with stale or fallback state. This is a hypothesis to investigate, not a confirmed root cause.

Comparing Chat model-picker state and catalog/entitlement refresh behavior before navigation, after returning, and after a full relaunch may help isolate the issue.

Workaround

Fully quit and relaunch the desktop app to restore GPT-6 options temporarily.

Related report checked

#43898 concerns Desktop Chat reasoning stuck on Instant. This report concerns GPT-6 options disappearing specifically after switching conversations, with a full relaunch restoring them.

Start by reproducing the macOS Desktop Chat flow: compare the model picker in conversation A, after switching to conversation B and back, and after a full relaunch. Investigate the conversation remount and model-catalog or entitlement refresh behavior described in the report; done means GPT-6 Pro and GPT-6 remain visible after conversation switching without requiring a restart.