Ticket #46076: 46076.diff

src/wp-admin/includes/post.php

@@ -429 +429 @@
                 }
         }
 
+        /*
+         * If this post save is actually a meta box save triggered immediately after an autosave from the block editor,
+         * we need to update the autosave date to after this save, so that it isn't auto-deleted as being outdated.
+         */
+        if ( isset( $_GET['meta-box-loader'] ) ) {
+                $autosave = wp_get_post_autosave( $post_id, get_current_user_id() );
+                if ( $autosave ) {
+                        /*
+                         * We need to wait for 1 second, to ensure the updated autosave will have a later
+                         * post_modified_gmt than the post updated above.
+                         */
+                        sleep( 1 );
+                        wp_update_post( $autosave );
+                }
+        }
+
         return $post_ID;
 }