I cannot reproduce the damage on misses. I've never seen this reported before, so it seems likely that if it is occurring for you, that it is the result of a mixture of effects. Can you provide me with a little bit more info? What classes are you using when this happens, what effects do you have up, and does it occur 100% of the time when a mob misses you, or is it a random occurrence?
I haven't had time to look into the reactive heal triggering, but I'll get to that as soon as I can.
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