Those belong to the sower tentacles, so we fix the issue on that end. But we're still not sure as to how you're able to pick up items that are not visible in the container. The corpses stack and all their items get transferred into a single container, but tentacles don't even leave corpses.
Did the tentacles die on the same tiles as the sowers? Are you collecting items during combat, perhaps? Are you using something like Cheat Engine or similar? Any extra info would be real helpful.
