Am I understanding you correctly: When you are at the login page, the username field is auto-populated with 'databaseName' ?
I'm pretty sure that what you're seeing is the autocomplete behavior your browser has natively. During the setup process you're asked for the username for your database and the input field name is 'username'. Then when you login to the front end of the site, we present you with a form, the input field name there is also 'username'. Your browser, not being the farthest spitting camel in the desert, doesn't know the difference between the two and blindly autocompletes the username to the last value you entered.