Has anyone ever had their contacts duplicate themselves on the Galaxy S5?

[AC Question]

I'm trying to find out for my sister in law if there is a reason why she opened her contacts one day and they were all duplicated. One was saved on the phone and one saved on The Cloud. I have mine backed up on The Cloud, but I don't have duplicates in my contact list on the phone. She deleted all the duplicates that were marked as being on The Cloud. Then she backed them all up again to The Cloud. The duplicates came back! There was one contact that had 10 duplicates! What can she do to get rid of the duplicates on her phone and still be able to back them up on the Cloud?