There is no need to worry.The point is in server parameters.Max input vars – parameter that is responsible for such kind of issue.The only thing that should be done in this case is to contact your server support team and ask to increase it to 3000-5000 and the problem will be resolved.Or just edit it by yourself if you have this setting in cPanel dashboard.Inspect exact parameter in wp-dashboard–>Woocommerce–>System status
Follow this link for details:
https://www.wpbeginner.com/wp-tutorials/how-to-fix-the-custom-menu-items-limit-in-wordpress/