I have the same issue in my tree. I felt like I had found the mother's name when it showed relationship "mother" for someone named Rachel. Then other records, including the cemetery file, said her name was Fredericka. I then found a census record where mother/daughter lived next door to each other and the mother was known as Riga (maybe they told the enumerator "Ricka"--a shortened version of Fredericka). With additional work on the tree, I now have 3 other woman who have used Rachel and Fredericka at different times. All are German, all were in the 1800s.