I never noticed any healing coming from his Sterilize, no matter how many debuffs he cleanses. I just had a PvP match, used Sterilize cleansing 3 debuffs, but the match ended before I could use Chemic Bath. Heimlock cleansed 3 debbufs, so he should have healed himself for 60k hp. At the end of the match, he had 0 healing score.
Also, the skill gets ready before it is actually ready. If you press on the icon the bar starts loading for a split second, disappears and does nothing. After one sec or so of tapping the button over and over, he finally starts casting it correctly. I only noticed this with Heimlock, but could happen with others