I'd not tried this ability before, but reading the tooltip, I decided I'd not worry about corruption. I'd just remove it once I'd leveled up. So I forged through dlevel 10 , wading through blobs of corruptions with my newly found awesome axe. Just as I finished clearing the level, I level up and get the skill. By this point, my gear is pretty seriously corrupted. My Xbow had taken the worst of it with around 12 corruptions, so that was my first target. I was *highly* surprised when I found out that it only removed one point of corruption at a time alongside giving a nasty debuff for 100 turns, but I figured, "Well, live and learn, I'll just clear off all this corruption as I go and be more careful next time." Except, after clearing off about 3 to 4 of the corruption off my xbow, the skill stopped working on it, failing 5 times in a row, even though it has 8 corruptions left. Now all my gear is stuck with tons of corruptions that the corruption removing skill won't remove. My torso armour has about 5 corruptions, and Flames of the heckforge has failed 4 times in a row on it. It certainly doesn't help that I despise the Demon Form ability you have to pick up to get to it and now I'm stuck with both useless skills. More than useless, given the huge rightous damage penalties.
That sucks, but thanks for the bugreport (I'll move this to bugs if you don't mind, since this isn't intended, that I know of)