It seems that there is a bug with the Illusory Weapon buff, when used on a Blueshine weapon, it does not become force (keeps blueshine material type), and hence takes damage. I noticed this in Deleras p2/3 while fighting all of the skeletons, my weapon was nearly completely broken. It should take no damage at all. This works fine for my main weapons, Greatswords, which are not blueshine.
I tried duplicating the problem in Spies in the House, plenty of skellys there too. Somehow, it took zero damage from those mobs. I kept using it until it took some damage again, this screenshot is from a loop through Lamordia rares, it again took damage.
I tried duplicating the problem in Spies in the House, plenty of skellys there too. Somehow, it took zero damage from those mobs. I kept using it until it took some damage again, this screenshot is from a loop through Lamordia rares, it again took damage.