Well it appears that in addition to the Halls of Origination "Bug" that I posted earlier regarding the first boss, the same thing has happened to Foe Reaper in Deadmines. I tried using Dragoneye's technique of standing my DPS/heals on the ledge and tanking him on the ramp, but as soon as he was going to charge a DPS, he bugged out, Evaded, and went to full health again.