Board Thread:Game Discussions/@comment-24149689-20140103120654/@comment-24142275-20140103121248

epic bosses are usually stronger during epic boss armor collection events(like the one for the winter keys), but also at the reward tiers (so 1,3,6,10,15,21,28,35,43,51 and 60).after every reward tier, they get a little weaker again. so most likely that's what's happening to you