I noticed an issue with hot bar items, when the item is dropped or used up a white mask of the original item still shows in the gui hotbar. If another item is dropped over the white mask item, this will clear that hotbar item. However i have lost items by dragging an existing item over another item in the hotbar. Example of dragging an axe over hotbar item2 which held a water bottle (both in my inventory), the axe when moved away shows nothing, and the water bottle is now gone from hotbar and inventory.

This happened to me, but with black jeans. After equipping them - dragging them onto my character from a dead body. Running around in 3rd person for couple seconds afterwards it looked like my legs where invisible, then it just fixed itself (redraw must have synced)