Eloqua creating Contacts with Old Email addresses when SFDC contacts are merged

Anybody else experienced this oddity? Have a solution by chance?

Example:

We have 2 contacts in Salesforce with the email address hello@gmail.com. Our SF team is on a dupe merge mission so those 2 contacts get merged into 1. Wonderful - HOWEVER - one of the hello@gmail.com contacts used to be goodbye@gmail.com. It was updated to the correct hello@ many years ago.

And for reasons unknown to us, hence this desperate plea for help, Eloqua creates a contact with the years-old, bad email: goodbye@gmail.com.

Any & all help is very much appreciated! Thanks!