third_party_invite_acceptance_stale· reason_code· applies to service_call, auth_decisionSub-reason for failed_precondition when a Station acceptance attestation is structurally valid but its signed expires_at has passed, observed_at is later than expires_at, or expires_at exceeds invite_expires_at. The verification service MUST fail closed rather than bind private invite material with an invalid or expired attestation. See zh/sync/third-party-invites.md section 7.5.