The user update page can only function as such if the constituent is logged in, if you navigate to that link as a non logged-in user it will function as a registration page, so you will see all of the information configured on the user registration page in the Standard Page Center. This isn't usually an issue because this page is generally linked to in emails where it can include an autologin link, or is accessed via your website when the constituent is logged in and goes to view their profile information, but can cause some confusion in testing when testers navigate directly to that link and do not realize they have to login first.