It was just a bug guys and Mythic squashed it! This is what Matt at the Herald had to say... There is a rumor going around the various fan sites that mage spell damage was somehow reduced in a "stealth nerf". This is not true. We had a bug this morning (one of the bugs that was fixed in the rolling patch) that resulted in sometimes random damages on monsters that were resistant/vulnerable to spell damage (this was the same bug that caused reistances not to print in your resistances window). So, earlier today, you could have easily seen a situation where you did less damage to a monster than in previous versions, but that was fixed. If it is still happening, it is a bug, not an intended damage reduction. Our intent was to raise spell damage (via resistence debuffs), not reduce it.