Duplicate Ticket Subjects Not Visible in Zendesk

Hello,

One issue we are seeing is for automated email reminders from certain vendors. If tickets have the same exact verbiage or subject as a previous ticket, then they do not show up in Zendesk. They are visible in our email inbox, just not routing to Zendesk. Do we have to create these tickets manually? Or how else do we make them unique so as to not miss them entirely? We want to make sure all emails get routed to Zendesk.

Thank you,

Kerry