Changing of menu item changes login form

Hi all,

I have a bit of a problem and I'm not quite sure how to tackle it. I have created a new menu that is set to display in a sidebar to authenticated users and contains only 3 items. One of the items links to 'user' so that the users can manage their account information.

I just found out that when I change the title of the menu item, it also changes the headline title of the login form. (see attached image) Why? And better do you have any ideas where I can look to solve this problem?

Any help is appreciated, thanks.