I was running Epic Lords of Dust and was mucking around and died (possibly normal/hard difficulty) while I had the Elder dryad summoned. What I noticed was that she attacking them and healing herself. However her mass heals also healed the cultists. I noticed in my combat log that 'you healed cultist for 150 etc'.
Now I haven't had a chance to go and in and test this again, however I haven't noticed a post regarding this so I thought I would bring this up, if anyone else noticed her mass heals affecting monsters please post here.
I will update this post if I get a chance to do some more testing.