relation_kind_watches_derived· reason_code· applies to event_envelope, schema_validationSub-reason for schema_violation when a direct ak.relation.create / update / delete targets relation_kind=watches. The watches Relation is a derived projection only: its truth source is the strand_watch typed current result written via the ak.strand.watch.set durable event, never a direct Relation write. See zh/models/relation.md §3.2 and zh/models/strand-and-message.md §8.