Summary

The action should have only one action type assigned.

Requirements

1. When editor add a new action, by default assign a default action type* to it. 
2. If user manually select multiple action type while add/edit of action, assign only first action type
3. same above behaviour should work in case of quick edit of action from admin action listing page.

* The Default Action Type setting is available in WP admin >> Writing Settings page (wp-admin/options-writing.php)