I have recently also seen a similar behavior except for me when I imported a FFF profile it overwrote some of my existing profiles.
So I have Printer A that I built a profile for since one did not exist.
Now when I get a profile from S3D for Printer A and do the import it overwrites my Printer A profile and replaces values.
However, it doesn't replace my profile but overwrites the values and still adds the new profile to the list.