I'm starting to see this when I or some other person creates a new profile: the Changes list has them "added as unrelated person" to a relative of the newly profiled person.
Example: Allinson-146. I created 7 of her children and attached them to her. I've seen this in my feed for others, as well.
It doesn't seem to show up in the profile otherwise, but it suggests that something has gone wrong somewhere in the process of creating new profiles.