Chat gets stuck on “Thinking…” while the response is actually completed and appears after forking

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

GPT 26.915.31945

What subscription do you have?

pro x20

What platform is your computer?

Darwin 25.3.0 arm64 arm

What issue are you seeing?

During a conversation, Codex sometimes becomes stuck in the “Thinking…” state and never displays a response.

Waiting does not resolve it, and sending a follow-up message also receives no response in the original chat.

However, when I fork the affected chat into a new chat, the previously missing assistant responses are present in the forked conversation. This suggests that the responses were generated/stored successfully, but the original chat UI failed to render or update them and remained stuck on “Thinking…”.

The attached screenshots show:

1. Original affected session: the conversation shows “Thinking…” / stopped state and does not display the assistant response.
2. Forked session: the responses that were missing in the original session are visible, confirming that output existed.

No explicit error message was displayed.

What steps can reproduce the bug?

1. Use Codex in an ongoing conversation.
2. Send a message and wait for the assistant response.
3. Occasionally, the chat remains on “Thinking…” indefinitely and no assistant response appears.
4. Send another message; the original chat still does not respond.
5. Fork the affected conversation into a new chat.
6. In the forked chat, observe that the assistant responses missing from the original chat are already present.

This is intermittent and I do not yet have a minimal code reproduction.

Affected original session ID: 01a0b97d-f006-73d0-b3f0-4cdcc3e3a352
Forked session ID: 01a0b9a7-d368-7a33-ba38-7f9d5a5310a1

What is the expected behavior?

Once a response has been generated, it should appear in the original conversation without requiring a fork. The chat should leave the “Thinking…” state, render the response, and accept subsequent messages normally.

Additional information

Screenshots

Original affected session

The chat remains stuck and does not render the assistant response.

Forked session

The previously missing assistant responses are visible after forking.

Start by reproducing the intermittent stuck “Thinking…” state in an ongoing conversation, using the affected and forked session behavior described in the issue. Compare the original chat’s state and rendering with the fork, and consider the issue resolved when a generated response appears in the original chat, the state clears, and follow-up messages work normally.