Amazon takes awhile now to register and acknowledge new products to your inventory under the new workflow.
In order to help with clarity, we have created a new UI indicator that helps sellers know how many products in their batch need more time to sync before you can fully complete the batch etc., which you will see in the FBA Inbound Plan context window.
Click on view items and you will see a drop down context window which shows you the products which still need time to process on Amazon.