I created a new preference for users (and made it available only on the profile page). But users cannot un-check the preference from their profile page. If they attempt to un-check it and press “SAVE” the screen reloads but the preference is still checked (and is still checked even accessing through the admin site).
Users can check a preference and save it, just not un-check it. The only way for us to un-check the preference is through the Newsletter plugin in WordPress admin.