After selecting the radio button you’ll need to click the SAVE FIELD MAP button at the bottom of the Field Map Layout. If you tried that, what message did you receive, if any?
We have not experienced a situation where the setting won’t save. But if we did, we’d try duplicating the Field Map Layout and setting the new layout as needed. If that does not work, we’d try deleting and adding back the first mapped field which will make Full Name the first mapped field.
Let us know if you are able to save the dataset name setting as we remain at your service.