Customizer broken

This seems to be the same issue as https://wordpress.org/support/topic/conflicts-with-customizer/ which is closed and I cannot reply to that topic, however I’ve managed to grab the errors being reported in my php log in hopes that this might help get the issue resolved. Restating the issue for this fresh topic, when using this plugin the cuztomizer will not display the site preview. The page appears blank, but in actuality the server is giving a 500 error and the following is places in the php error logs. ` [28-Dec-2018 18:54:20 UTC] PHP Fatal error: Uncaught Exception: Illegal widget setting ID: nav_menu_item[559-navception1] in ./wp-includes/customize/class-wp-customize-nav-menu-item-setting.php:171 Stack trace: #0 ./wp-includes/class-wp-customize-nav-menus.php(692): WP_Customize_Nav_Menu_Item_Setting->__construct(Object(WP_Customize_Manager), ‘nav_menu_item[5…’, Array) #1 ./wp-includes/class-wp-hook.php(286): WP_Customize_Nav_Menus->customize_register(Object(WP_Customize_Manager)) #2 ./wp-includes/class-wp-hook.php(310): WP_Hook->apply_filters(NULL, Array) #3 ./wp-includes/plugin.php(453): WP_Hook->do_action(Array) #4 ./wp-includes/class-wp-customize-manager.php(926): do_action(‘customize_regis…’, Object(WP_Customize_Manager)) #5 ./wp-includes/class-wp-hook.php(286): WP_Customize_Manager->wp_loaded(”) #6 ./wp-includes/class-wp-hook.php(310): WP_Hook-> in ./wp-includes/customize/class-wp-customize-nav-menu-item-setting.php on line 171 `