So this happens becuz of Sorting feature i believe. When you sort items by any type, dropping an item will almost guarantee you dropped the wrong item. After dropping items you have to 100% make sure you dropped the correct items by looking at the loot bag at your feet. It happened to me while playing and I dropped some Ichor and some Bones from my inventory, but in reality I dropped my legendary eye patch Blindsight and Khari Waterskin. If I didn’t check what I dropped I would actually lose those precious items. Always make sure to check what you drop!