If you pick up an item and are in the range of another instance of the item it picks up one and destroys the other
I have tried to recreate the bug and instead of deleting one item when picking up the other I was able to pick up one of the two with the image of the item staying then when i tried to pick it up it did not appear when picking it up.
This may not be related to picking it up at the same time.
Both times I have observed the bug the deleted item has been shockwave.
I attempted to recreate it with the knife but it worked as intended.