Index: src/wp-includes/nav-menu.php
===================================================================
--- src/wp-includes/nav-menu.php	(revision 36513)
+++ src/wp-includes/nav-menu.php	(working copy)
@@ -758,7 +758,7 @@
 				}
 
 				$menu_item->type_label = __( 'Post Type Archive' );
-				$menu_item->description = '';
+				$menu_item->description = '' == $menu_item->post_content ? $object->description : $menu_item->post_content;
 				$menu_item->url = get_post_type_archive_link( $menu_item->object );
 			} elseif ( 'taxonomy' == $menu_item->type ) {
 				$object = get_taxonomy( $menu_item->object );
Index: tests/phpunit/tests/post/nav-menu.php
===================================================================
--- tests/phpunit/tests/post/nav-menu.php	(revision 36513)
+++ tests/phpunit/tests/post/nav-menu.php	(working copy)
@@ -180,4 +180,38 @@
 
 		$this->assertEquals( $nav_menus_names, $expected_nav_menus_names );
 	}
+
+	/**
+	 * @ticket 35324
+	 */
+	function test_wp_setup_nav_menu_item_for_post_type_archive() {
+
+		$post_type_slug = rand_str( 12 );
+		$post_type_description = rand_str();
+		register_post_type( $post_type_slug ,array(
+			'public' => true,
+			'has_archive' => true,
+			'description' => $post_type_description,
+			'label' => $post_type_slug
+		));
+
+		$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->assertEquals( $post_type_slug , $post_type_archive_item->title );
+		$this->assertEquals( $post_type_description , $post_type_archive_item->description ); //fail!!!
+
+		$custom_description = rand_str();
+		wp_update_nav_menu_item( $this->menu_id, $post_type_archive_item_id, array(
+			'menu-item-title'       => 'WordPress',
+			'menu-item-description' => $custom_description
+		) );
+		$post_type_archive_item = wp_setup_nav_menu_item( get_post( $post_type_archive_item_id ) );
+		$this->assertEquals( 'WordPress', $post_type_archive_item->title );
+		$this->assertEquals( $custom_description, $post_type_archive_item->description );
+	}
 }