Duplication of contacts from somewhere

I have two Address Books setup, "Personal" and "Business" (both "On this computer"). I currently have Automatic Contacts - "Automatically create entries in the addressbook when responding to mail" disabled under Evolution Preferences.

I create a Contact in my Business folder for one of my other email addresses (so I can test). With autocompletion enabled for both Contact lists, I create an email to my alternate account and it finds the email address appropriately. I send off the email. From that alternate account, I reply.

Back in evolution, I receive that reply from the alternate account. I hit Reply and send.

Instantly, I'm now facing a new Contact in my Personal address book, despite 1) Automatic Contacts being OFF and 2) it already exists in Business.

So, my question is: what the heck? I'm expecting no automatic contact at all with my current settings. If I did enable automatic contacts, I would expect that duplicates wouldn't be created.

Using V2.12.1.