Ticket #44183: 44183.2.diff

src/wp-includes/class-wp.php

@@ -597 +597 @@
                         $GLOBALS['single'] = 1;
                 }
 
-                if ( $wp_query->is_author() && isset( $wp_query->post ) ) {
-                        $GLOBALS['authordata'] = get_userdata( $wp_query->post->post_author );
+                if ( $wp_query->is_author() ) {
+                        $GLOBALS['authordata'] = get_userdata( get_queried_object_id() );
                 }
         }