Current behavior for when you have the system preference for AutoCreateAuthorities set to generate and BiblioAddsAuthorities set to allow, when creating new authority records for 100 & 700 tags, it also creates relator terms. Steps to recreate: When you save a bib record in the basic editor, authorities are connected or created if the system does not have that authority. When Koha creates new authorities for 100 & 700 tags for people it also brings the relator term into the new authority. Most people do not want relator terms in their authority records so they need to inspect their personal authorities and bring in the proper authority from LC (or another source).
From reading bug 24675 I believe that this is fixed - please reopen if I am mistaken.