There could very well be some sort of corruption to your sync account if you see duplicates. One way to resolve the issue is to reset and resync your database. Here are the directions to try...

1.) First, make sure you are signed out of your Mariner Cloud account (you can do this from the MacGourmet Deluxe Preferences). Access the Sync Manager in MacGourmet Deluxe, sign in, then click the reset button as shown in the image I have attached. That will strip all the sync data out of the database, do not delete it as the dialog says.