To fix this, you'll need to create a list to see who has the incorrect field tied to them. To create the list, navigate to:
  1. Navigate to Lists > Manage Lists
  2. Click the Manage basic and advanced lists block under List Actions
  3. Click Add > Create Advanced List
  4. In Select Objects, scroll down to Constituent Information
  5. Select User Base
  6. In Select Objects, scroll down to Constituent Information
  7. Select User Citizenship/Residency
  8. Display Fields
  9. Select Fields
  10. Expand User Base
  11. Mark First Name and Last Name
  12. Expand User Citizenship/Residency
  13. Mark Citizenship
  14. Select
  15. Preview
This will display all users and their citizenships. To see who the outliers are that are causing this error, filter by the field you're trying to cleanup by adding the filter User Citizenship/Residency.Citizenship is any of and include the field here.

After seeing who the outliers are, navigate to their profile under:
  1. Core > Users/Access > Profile > Edit User Profile Data
  2. Search the user
  3. Edit Personal Information
  4. Delete the Citizenship from that location
If the citizenship is needed, you can go to Core > People Finder > search the user > Contact Card and add the correct Citizenship field from the dropdown.