I didn't see a registration page.
I saw a login with username and password box. Between them were two radio buttons. One said Create New Acct (or similar) the other said "Existing Account" (or similar). It seemed obvious that I could put in a username and password and click "Create New Acct" to register. But when the "Create New Acct" radio button was checked I could enter a username but not a password.
By clicking "Existing Acct" I could fill in both a username AND a password -- and then click Create New Acct and when submitted that registered my new acct.
It seems, that "Create New Acct" should either take me to a dedicated registration screen, OR it should let me pick a username and a password to begin the registration process.
Maybe, it shouldn't have worked at all -- but it worked in a totally unexpected way.