By default, DISCO does not deduplicate productions against each other. Each production stands on its own and doesn't impact future productions.
To deduplicate across productions:
In the DISCO main menu, click Productions.
On the Productions page, on the production card you are working with, click on the number linked under Documents to search for produced documents.
Click the mass tag icon.
Apply a tag (such as Work-Product) to all produced documents.
When you create your next production, add the 'Work-Product' tag to the Exclude documents tagged box. Any documents tagged as 'Work-Product' will then be excluded from your production.