A hub teardown no longer reports work it went on to finish

On 2026-09-07 at 21:39:38Z one sync/ hub on memex logged this and opened an incident:

[DISPOSE-DISCARD] Hub sync/KptJzzVNdk2qCCf4nMvcSA is disposing with 1 turn(s) still queued and
unprocessed (the pump stops with this call). RunLevel=ShutDown; 0 deferred delivery(ies) already
answered ShuttingDown; last turn executing: ShutdownRequest.

It reads as the drain contract broken — teardown lets accepted work finish — and it names no message, so the investigation could get no further than "a late post beat the pump by milliseconds".

The pump does not stop with that call and cannot. messageService.Dispose() runs from inside the hub's own ShutdownRequest turn, so the turn loop is one stack frame below it and takes the next turn the instant that turn returns. Reproduced deterministically: 3 ms after the Error, the same hub logs is disposing. Not processing DisposeRequest (id=…) — it had dequeued the delivery the Error called unprocessed, and the disposing seam had answered it (a transient ShuttingDown NACK to anything a sender awaits, a silent drop for fire-and-forget traffic nobody awaits). Nothing was left waiting. The Error was the defect.

Three changes, all at the cause:

• The gate stops creating the state. The intake gate exempted teardown's own traffic at every run level, so a DisposeRequest arriving after the hub had begun disposing was admitted into a window where its handler is a proven no-op — it could do nothing but occupy a turn slot the disposal report would then find. The exemption is now bounded by the phase that can still use it: ShutdownRequest while a phase is left to advance, DisposeRequest only before the hub's own teardown has begun. A recycle sent to a live hub is unchanged, and has a control arm in the test that says so.
• The report measures. It stays an Error only where "queued and unprocessed" can be true — nothing is draining the loop, so nobody will take those turns. Otherwise it is a Debug line saying the pump drains them next.
• It names the message. Both forms now print the queued deliveries' type, id and sender.

The finding and the reproduction are in Teardown layers → "What a hub still discards", and the run-level monotonicity it also secures is in Teardown verdicts are causal.