Quick registration fields - double email entries showing and blank empty bar

Hello there,

i was trying to edit the quick registration fields to just limit to the following :

1. First / last name
2. Preferred Username
2. Email address

i did the settings in the workflow section under users and it seems theres a double entry for the email address field each time i enable it under "quick registration".

Also , under the preferred username section, it doesn't seem to display the description even though i enabled it ?

is there any guide to setting these custom quick registration fields, as i was going through the documentation online but could't find any specific to this (apart from customizing the template).

thanks !

regards
Alex