I do see several queries like:

SELECT namespace, object_id, relation, userset_namespace, userset_object_id, userset_relation, caveat_name, caveat_context FROM relation_tuple WHERE pg_visible_in_snapshot(created_xid, $1) = $2 AND pg_visible_in_snapshot(deleted_xid, $3) = $4 AND namespace

some finish in just a couple ms.. others are taking like 500ms to return