This likely happens when a new a New Vendor Item is created upon entering or import of a line item invoice.  Before creating a new Purchase Item to link to the Vendor Item, always check to see if the Purchase Item exists in the database.  You often can have many Vendor Items linked to a single Purchase item. 

The decision as to whether a new vendor item should be linked to an existing Purchase Item or a new Purchase Item is often straight forward but sometimes more complex.  For example you may purchase two types of Tuna.  If they are both used for the same menu items they should be one Purchase Item. All Vendor Items for Tuna should link to the one Tuna Purchase Item. However, if you have a #1 Tuna for Sushi and another Tuna for a different entree, you should create two Purchase Items.

Scott Gillman

Dine Technology