This buff is silly. I finished the Oceanfell zone on my main (Wizard) and primary alt (channeler). Issue is, every hit by my wizard triggers the 5% damage cap buff which essentially makes the mob immune/highly resistant to damage until it falls off. This applies to each of the summoners/arms and final named. This means every spell I cast results in a period of time of doing no damage. Causing the final summoners and arms to take forever to kill. Conversely, I take my channeler in who is FAR less dps. He steamrolls the final named in no time at all because he doesn't trigger the 5% cap. Is it really the intent of a zone that I should look for low level spells on my wizard or take off gear so that I am not pushing up against a ridiculous buff repeatedly?
I have no idea what the purpose of the Stoneward buff is, aside from annoying players. As a game mechanic, it's tedious and unfun.
This is an effect from expansion bosses (5% for solo, 10% for heroics). It is now removed from Live Event dungeons.