Negative Landed Cost Accounting and Calculation

What is your valuation method on this item? Probably what happened was some part of the inventory from the original 2 receipts was already sold. The system took that into account and adjusted the cost of the remaining inventory proportionally to what was remaining and COGS to what was sold.

We use Average method on this item

Yes, most likely it is the scenario that I described.
The system is only allowed to adjust the Inventory Account for the portion that you still have in stock, the rest of the adjustment goes into the COGS as these inventory is already sold.

Got it, thanks! Just one quick question: if I use a negative adjustment to move the amount from COGS to Inventory in this scenario, does that mean the item cost won't be right?

Yes, that’s correct — if you use an inventory adjustment to move the amount from COGS back to Inventory, it will affect the value of the current on-hand inventory and can change the average cost going forward. In this case, Acumatica is putting part of the adjustment to COGS because those units were already sold, so there is no inventory left for that portion to adjust. I would not recommend moving it back to Inventory unless you intentionally want to change the current inventory valuation. If the account is the concern, it’s better to review the posting setup or reclass the expense side, not force it into inventory.