I've noticed that sometimes when I click on corpses and it says I gain some loot, the item never appears in my inventory.
The latest one I noticed was in the friendly spider caves, where if you rescued one of their spiders from the Areana, then they open the webs for you and you can go back there and loot stuff.
When clicking on the corpse, it says I found a Malachite Brooch. No item appeared in my inventory though. I reloaded, tried again, and still nothing. I examined my inventory before and after, and no new items.
I've seen other cases where I think the same thing is happening. It says something like You found a crystal. I look through my inventory, and cannot find a crystal. I assumed those might have been stacking with one of the other crystals, but hard to say since it doesn't say what type of crystal I got. If its just supposed to be an item called "Crystal", then it definitely never appeared.
This doesn't happen with all items. Just some.
Windows 7 x32, Steam version.