@Aman_Jaffer what seems to be happening is that even though your quantity is positive. Total cost is negative. Manager will automatically transfer negative cost out of balance sheet to profit & loss statement. This will make your cost of unsold items zero.
If you buy item for 5.5 but unit cost seems to be 15.82 and inventory cost correction doesn’t see any discrepancy. Then there must be a bookkeeping error somewhere.
The easiest explanation (that will explain positive quantity but negative cost) is that you might have entered credit adjustment with very large cost.
The screenshot you have posted shows just a few transaction, it doesn’t show the entire history for the item. You might need to go a few pages back to see when unit cost became 15.82. I’d assume this is where bookkeeping error has occurred.
If you still can’t see it, PM me and share with me access to your accounting file and I can look into this specifically.