direct_conversation_pair_materialization_conflict· reason_code· applies to event_envelope, auth_decision, state_resolutionA second accepted Direct Conversation Realm was observed for the same pair_key while both carried apparently valid founder admission, four exact Events, four consecutive source RealmCommits and founding-authority evidence, indicating slot, cutover-fence or signature equivocation by a trusted current Station. Both Realms freeze new Message, membership, policy, MLS and binding writes and all evidence is retained; implementations MUST NOT pick a winner by Realm-token lexical order or arrival order, tombstone either Realm, or migrate history. See zh/identity/contact-and-direct-conversation.md §5.7.