The server ledger is cleared by an explicit ack, never by the check-in response, so a dismissal that cannot reach the service must be persisted and retried or the device rings again later. Add a durable pending-ack queue (404 means the alert ended: settled, drop it), map the 409 ERR_ALARM_TRIGGERED_OFFLINE check-in into a normal trigger for the same takeover, and make a 404 an ending rather than a missed alarm. This also carries the expiry/endings state the screens render.
