How did happened? Duplicate contact

Photo says it all … email domain are both exactly same but was edited out for privacy

Both are same person and have same email address but different database id

Is email address the primary key in Mautic → I checked and Email is set Yes on Unique Identifier in custom field settings

It would help if you’d explain how the contacts were created. I saw the same behavior when editing the contacts manually.

I look at both contact history. This contact is one of our staff member. He receives a newsletter that we sent out weekly so when we switched from Sendy (former mailer) to Mautic, we imported all contact over to Mautic via CVS file.

I can see both contact have same history and both was created same day 2 month ago until recently I imported a new CVS for a “Staff only” segment and that when it seem to duplicate the contact into two contact but still same name and email address.

Funny thing is history show “Contact updated” instead it duplicate the two. The only difference between two contact is one have a “staff” tag on it.

I did some testing beforehand to make sure that importing would merge the contact instead of creating a new secondary same contact and it did pass the test that it merged which I wanted in the first place.

Here a screenshot of both contact history … in history comm.cvs is the list I imported to add those who are communication staff

There are only 12 staff on communication team and I checked all contacts history. There was only one that was duplicated. The rest of the contacts in staff CVS was merged successfully.