The "duplicate product" action has a limited functionality and offers a quick way of creating a new product with the basic characteristics of the source (name, descriptions, price, quantity). It does not actually clone the product with all the elements, you need to update them manually afterwards. This was already specified in the Release notes (Quickupdate 4.0, point 6): http://prestashop.endpulse.com/forum/index.php?topic=11.0"6. Added "Duplicate product" action - quickly duplicate any of the products in your list. Is provides a rather limited functionality, duplicating only the product features present in the list (not images & attributes)"
Moreover, regarding your previous question, the new product will not be active
by default exactly because it needs to be manually edited with all the remaining elements.