Id prob combine an outbox with provider side idempotency. The fenced database transaction records the accepted result and its outbound intent together, so a superseded worker cant enqueue new work. The dispatcher then retries that intent using a stable idempotency key for the logical operation. An outbox doesnt guarantee "only the current owner ever sends". An intent accepted before ownership changed can still be delivered afterwards, and a dispatcher can itself pause with a request in flight. If that previously accepted action must now be rejected as obsolete, the destination needs a version or conditional operation check too. Idempotency alone wont establish that. Where the provider offers no check, you have to decide whether accepted intents remain valid or whether the workflow needs cancellation, reconciliation or compensation.