Help: Our Event Registration payments are auto-linking to outstanding pledges

When I bring over NetCommunity Event Registrations into a batch and commit - any registrant that happens to have an outstanding pledge or recurring gift will have their registration fees automatically applied as a payment to that pledge/recurring gift.  I am not linking them manually -- and I am not getting a prompt by RE before it's linked.  Any ideas as to why this happens or how I can prevent?  Thanks!!