Warning: Creating default object from empty value

Hi! thanks for the work with this plugin.
I’m getting:
“Warning: Creating default object from empty value in …\wp-content\themes\themename\library\core.php on line 3259”

{main}( ) ..\admin-ajax.php:0
do_action( ) ..\admin-ajax.php:85
call_user_func_array: \plugin.php:496} ( )
wp_ajax_add_menu_item( ) ..\plugin.php:496
array_map ( ) ..\ajax-actions.php:1091
wp_setup_nav_menu_item( ) ..\ajax-actions.php:1091
apply_filters( ) ..\nav-menu.php:774
call_user_func_array: ..\plugin.php:213} ( )
cb_megamenu_walker_loader( ) ..\plugin.php:213

I get this warning when I add the menu in menu settings over the added menu.
theme problem maybe?

https://www.ads-software.com/plugins/shortcode-in-menus/