The issue with this boss is that Rune of Grasping Earth is bug, because when you're in http://www.wowhead.com/spell=157060/rune-of-grasping-earth you must to be immune to physical damage or, said in other way, you become immune to the damage of the http://www.wowhead.com/spell=157054/thundering-blows while you' re in Rune of Grasping Earth, only will receive damage from that, so, please, fix it, because all the raid receive ticks of 54-55 ks of damage, although you're in Rune of Grasping Earth.
You aren't getting damage from other sources, the spell its working right.
The only remaining bug on Kromog it's that he cast his spells too often compared to retail, he cast rune of grasping at 50s more or less when on retail this is casted on 1:20+
We tested 2 days ago with our alts in hc, and we did'nt find this issue, you don"t become immune to the damage just a big reduction of the Thundering blow's damages.
While in the Rune of Grasping Earth, you'll receive 90% less damage in normal difficulty, 80% less in others. And it's working fine. ;)
