On the third floor of the Police Station in Gorka on the half circle platform by the stairwell, whenever you drop an item from your inventory it will disappear.
I dropped my ammunition box hoping to reload my magazine, the ammunition box did not appear. I even proceeded to look for it in the lower floors (all the rooms) and even outside of the building. I cannot find it.
I reproduced it again by dropping a headtorch. I cannot find it either.