What happens

A Telegram topic can still look bound to Codex after /cas_resume, but normal messages in that same topic stop reaching the thread.

Repro

1. Open a Telegram topic that already used CAS.
2. Resume a thread from /cas_resume.
3. Confirm /cas_status says the topic is bound.
4. Send a normal message in the topic.

Expected

Once the topic is resumed and bound, normal messages in that topic should keep going to the same Codex thread.

Actual

The topic can look healthy from /cas_status, but plain inbound messages miss the binding and fall through.

Notes

The April 11 incident pointed to binding drift more than a dead Codex thread. Manually running /cas_detach and then /cas_resume against the same thread fixed the topic immediately.

So the real issue is broader than a single inbound-lookup miss:

• a stale topic binding can stick around longer than it should
• repeated resume attempts can leave old resume callbacks behind for the same topic
• the current logs do not say enough when a binding gets cleared or detached