Hi @lauraherrera , my name is Jason, I’m on the Ads team here at HubSpot. It is possible for the Facebook lead ad sync to create duplicate contacts if the submission coming from Facebook doesn’t have enough data for our CRM to automatically dedupe. For example, if the names don’t match perfectly, or the emails are slightly different, or if what is submitted is only a First name. You can tell if the contact came from a lead ad by going to the contact timeline and looking for a form submissions event that says the form was submitted on Facebook Lead Ads.