I have cast this spell multiple times in various fights. Occasionally, I will get a nice hit from it and not get a full health return. An example it will do 265 damage and I will get 178 health back. Most of the time it will do 115 damage and give back 115 health, or will do damage with no health return. I have noticed that the only time it seems to not give back 100% is on a critical (red numbers) hit. I do not have full health when this happens, although I have not noticed if it is chopping off where I would be at health without balms or food type items. Hedike advised me to post this here. Remy has told me this happens to him as well.