session_grant_replay_expired· code· HTTP 410· scope endpointA durable exact-replay lookup found the original SessionGrant issuance outcome, but its immutable expires_at is past. The response details MUST include grant_id and state=expired. The issuer MUST NOT return the expired credential as success or issue a replacement under the same request identity; the client must perform full authentication with a new one-shot proof and request identity.