Well... at least you cannot drop it on the ground or hand it back and forth between characters. Which you *can* do with the Shadowblade version from Arabella's ring (I've made my own thread about that issue).
Also: I did use the upcast spell-version before switching to the ring's and I noticed that the damage glitch would happen (for *some* reason) even if I didn't apply any coatings, dips, etc. I wasn't able to find out what exactly caused the bug to fire - I did check to see if it was Arcane Synergy items as these could be viewed as applying a buff/condition to the blade, but that wasn't it.