On playing today I have noticed that the arquebus Three Bells Through cannot destroy normal/gunpowder, or other similar objects. It can however destroy sigils. I suspect this is an unintended interaction with its line shot property. Anyone equipped with the weapon will keep uselessly shooting the barrel until given a different order.
Also encountered this bug with Gaun's Share.
Edit: I just killed the enemy that drops Oidreacht and sure enough when you pick up the weapon it has draining but if you reload the game it is gone.