I’m syncing WorkflowMax contacts to HubSpot. What happens if a contact appears twice under different clients in WorkflowMax?

A contact is uniquely identified in HubSpot by his or her e-mail address. If a contact exists in WorkflowMax under two or more clients (and all instances of that contact share the same e-mail address), the most recently modified instance of that contact is what will appear in HubSpot.