Sorting Contacts by last names

[plugandplay]

Have a Galaxy S3. My Contacts are sorting mostly by last name, but 10%+ of my Contacts are sorting by first name.


Already have gone into Contacts > clicked on the Menu and selected Setttings > selected 'Display contacts by' and choose Last Name, also have Edited the contacts in question and see that they are, like the others which are sorting correctly, entered in as First Name First and Last Name Last.