Hi Jason,
I assume you have a dedicated CRM Update program? The CRM update program is usually configured not to do a force lead creation unless neither a lead or a contact exists. To do a force lead creation, I recommend creating a dedicated program that fires the Create Lead custom event. You can also configure that program to only fire if a lead doesn't exist just to ensure duplicate leads aren't created. Below is a screenshot of a custom program designed to do force lead creations.
Hope that helps.
Cheers,
Ryan