Ticket #31099: 31099_Docs.patch

src/wp-includes/post.php

@@ -3965 +3965 @@
          *
          * The dynamic portions of the hook name, `$new_status` and `$post->post_type`,
          * refer to the new post status and post type, respectively.
+         * 
+         * publish_{$post->type} fires on first publish and subsequent updates.
+         * If you are looking to only fire a callback when $post->post_type is first
+         * published, use transition_post_status instead.
          *
          * @since 2.3.0
          *