I crafted an improvised stone knife. When I placed this into my hands to open a can of tactical bacon there was a "duped" stone knife in my inventory.

When I clicked to remove it from my hands it appeared as though I had 2 stone knives in my backpack (worn red dry bag).

I was able to click and drag the stone knife into other available empty slots in my dry bag and it still appeared as though I had 2 (but I didn't actually have 2).