Missing Units Added to Shipment from a Year Ago


I recently sent my first pallet of product into Amazon, 4 SKUs about 700 units total. 1 had the correct count, 2 SKUs were over by 1-2 items, and the last SKU was short over 50 units.

I waited until I could finally reconcile and sent in a copy of my invoice showing how many units I purchased and another invoice showing those same number of units prepped by my 3PL.

Today Amazon responded and said they found the missing 52 units and added them to another shipment with that same SKU from a year ago. Has this happened to anyone else before? I don’t understand why they wouldn’t just add them to the shipment that they’re missing from. It’s obvious I have not had 52 units that were delivered a year ago just sitting around and miraculously sent in 52 less in this pallet despite all evidence to the contrary.