diff --git a/src/wp-includes/nav-menu.php b/src/wp-includes/nav-menu.php
index 7208d9bbf5..70a450e395 100644
--- a/src/wp-includes/nav-menu.php
+++ b/src/wp-includes/nav-menu.php
@@ -762,13 +762,15 @@ function wp_setup_nav_menu_item( $menu_item ) {
 				$object =  get_post_type_object( $menu_item->object );
 				if ( $object ) {
 					$menu_item->title = '' == $menu_item->post_title ? $object->labels->archives : $menu_item->post_title;
+					$post_type_description = $object->description;
 				} else {
 					$menu_item->_invalid = true;
+					$post_type_description = '';
 				}
 
 				$menu_item->type_label = __( 'Post Type Archive' );
 				$post_content = wp_trim_words( $menu_item->post_content, 200 );
-				$post_type_description = '' == $post_content ? $object->description : $post_content; 
+				$post_type_description = '' == $post_content ? $post_type_description : $post_content; 
 				$menu_item->url = get_post_type_archive_link( $menu_item->object );
 			} elseif ( 'taxonomy' == $menu_item->type ) {
 				$object = get_taxonomy( $menu_item->object );
diff --git a/tests/phpunit/tests/post/nav-menu.php b/tests/phpunit/tests/post/nav-menu.php
index d2cec8039b..693f1fb40a 100644
--- a/tests/phpunit/tests/post/nav-menu.php
+++ b/tests/phpunit/tests/post/nav-menu.php
@@ -258,4 +258,21 @@ class Test_Nav_Menus extends WP_UnitTestCase {
 		$this->assertEquals( $post_type_slug , $post_type_archive_item->title );
 		$this->assertEquals( $menu_item_description , $post_type_archive_item->description );
 	}
+
+	/**
+	 * @ticket 35324
+	 */
+	function test_wp_setup_nav_menu_item_for_unknown_post_type_archive_no_description() {
+
+		$post_type_slug = rand_str( 12 );
+
+		$post_type_archive_item_id = wp_update_nav_menu_item( $this->menu_id, 0, array(
+			'menu-item-type'   => 'post_type_archive',
+			'menu-item-object' => $post_type_slug,
+			'menu-item-status' => 'publish'
+		) );
+		$post_type_archive_item = wp_setup_nav_menu_item( get_post( $post_type_archive_item_id ) );
+
+		$this->assertEmpty( $post_type_archive_item->description );
+	}
 }