If there are other users (such as Grandparents) on the profile update form, their first and last names must be added in order for the form to submit without error.

This can also happen if one parent is auto-populating their household information and a spouses household information. In this case the user should
  1. Remove the Mother, Father and Student from the Form.
  2. Save the Form
  3. Add the student back as a User Regarding.
  4. Re-enter the information for both the mother and father.