Registration Screen (include profiles) profiles cant share same field

CiviCRM 2.1.alpha1

If profiles share similar fields e.g.

Profile top of page [STUDENT]
First Name: Jane
Last Name: Doe
Grade: 5

Profile bottome of page [PARENT]
First Name: John
Last Name: Smith
Emergency Contact: 9999999

On processing the [STUDENT] profile

{First Name}

and

{Last Name}

are overwritten by the profile [PARENT]. The work around for me was to create custom data:
student fname and student lname.
and apply this to the Profile [STUDENT].