Need assistance with unexpected FNSKU sent to FBA?

Anyone else getting this message recently when trying to locate alleged missing units from shipments into FBA?

"you sent with shipment FBA18KPG1Z8P have arrived at our fulfillment center as an unexpected FNSKU when compared to your shipping plan. Unfortunately, we are unable to recover the physical inventory of the located item at this time, due to the error in shipment plan creation. We are unable to reimburse or reconcile the discrepancies you have asked to investigate for these items because of the error."

I have been sending in product for for about 8 years and have never received this. Now twice in the last week I have received this. Is this Amazons new way to not pay for losing inventory?

Hopefully this will help get my claim somewhere.

First shipment was B0048IFCRG- sent a case pack of 12 direct from the manufacturer. They claim 6 units were good and 6 were a different FNSKU but they cannot locate those 6 to prove they were something different and refuse to reimburse us. Asked for a call back over a week ago with no response and a open case still

Second shipment was FBA18KPG1Z8P- Sent in 3 units in this box. I have been sending this item in for over a year with no issues. They claim they received a different FNSKU but cannot locate the item to prove to me what they claim to have received.