Membership 2 Pro Plugin PHP CPU


My site is not working well because Membership 2 Pro Plugin uses too much CPU 98% and I often get 500 Internal Server Errors:
-If I try to export data from /wp-admin/admin.php?page=membership2-settings&tab=import I get a 500 Internal Server Error and mysql hits a CPU of 97%
-If I go to a page with the following shortcode the CPU hits 98% : [ms-membership-account show_profile="no" show_invoices="no" show_activity="no"][ms-membership-login register="no" label_username="E-mail" label_lost_username="E-mail"]
- If I go to this page with Query Monitor 2.13.2 installed and logged out I get 500 Internal Server Error.

I have isolated the problem to discard other plugins and now I have a version with the following components and all are new:
- Wordpress 4.7.1
- theme: Twenty SixteenVersion: 1.3
- plugin:
- in w-config: define('WP_MEMORY_LIMIT', '3000M');