diff --git a/src/wp-includes/class-wp-admin-bar.php b/src/wp-includes/class-wp-admin-bar.php
index dfebbb20e4c86..7925ef2e9f579 100644
--- a/src/wp-includes/class-wp-admin-bar.php
+++ b/src/wp-includes/class-wp-admin-bar.php
@@ -169,7 +169,7 @@ public function add_node( $args ) {
 			'my-blogs'               => array( 'my-sites', '3.3' ),
 		);
 
-		if ( isset( $back_compat_parents[ $args['parent'] ] ) ) {
+		if ( is_string( $args['parent'] ) && isset( $back_compat_parents[ $args['parent'] ] ) ) {
 			list( $new_parent, $version ) = $back_compat_parents[ $args['parent'] ];
 			_deprecated_argument( __METHOD__, $version, sprintf( 'Use <code>%s</code> as the parent for the <code>%s</code> admin bar node instead of <code>%s</code>.', $new_parent, $args['id'], $args['parent'] ) );
 			$args['parent'] = $new_parent;