device_directory_unavailable· reason_code· applies to service_callThe requester's own Station could not obtain or verify a current attested device projection for an exact (account_id, device_id) on this call. It reports only the fetching Station's result, never target state, and MUST NOT be rendered as an omitted row or an empty device list. See zh/crypto-media/device-lifecycle.md section 8.2.1.