I'd say the bug doesn't need to be fixed but rather they need to just level cap the 85 earring and remove the set bonus from all future gear. If a class pulls competitive DPS like a warden does it shouldn't be capable of debuffing the mobs to this degree. 5-10% mit debuffs are fine for DPS to use, anything over that should purely be the realm of the support classes.
And 5-10% is what you get as DPS unless you use earring(that might change if they decide to put more +dot pulses to traits).People have been bringing atention to earring for years now.15 20% on tank gear and only on tank gear or yellow would be fine.After that we would still look to either nerf fire debuffs/physical debuffs or give warden ~15-20% mitigation bypass so every dmg dealer has equal mitigation level target.After that you can balance DPS on each class a bit easier.