diff --git a/src/server/game/Entities/Unit/Unit.cpp b/src/server/game/Entities/Unit/Unit.cpp
index f87548d18..f37d493ec 100644
--- a/src/server/game/Entities/Unit/Unit.cpp
+++ b/src/server/game/Entities/Unit/Unit.cpp
@@ -1345,7 +1345,7 @@ void Unit::CalculateSpellDamageTaken(SpellNonMeleeDamage* damageInfo, int32 dama
     }
 
     int32 cleanDamage = 0;
-    if (Unit::IsDamageReducedByArmor(damageSchoolMask, spellInfo))
+    if (!spellInfo->HasAttribute(SPELL_ATTR4_IGNORE_DAMAGE_TAKEN_MODIFIERS) && Unit::IsDamageReducedByArmor(damageSchoolMask, spellInfo))
     {
         int32 oldDamage = damage;
         damage = Unit::CalcArmorReducedDamage(this, victim, damage, spellInfo, 0, attackType);
diff --git a/src/server/scripts/Northrend/Naxxramas/boss_gluth.cpp b/src/server/scripts/Northrend/Naxxramas/boss_gluth.cpp
index 7076ab750..c57bc427e 100644
--- a/src/server/scripts/Northrend/Naxxramas/boss_gluth.cpp
+++ b/src/server/scripts/Northrend/Naxxramas/boss_gluth.cpp
@@ -256,7 +256,7 @@ class spell_gluth_decimate : public SpellScript
                 return;
             }
 
-            GetCaster()->CastSpell(unitTarget, SPELL_DECIMATE_DAMAGE);
+            GetCaster()->CastSpell(unitTarget, SPELL_DECIMATE_DAMAGE, true);
         }
     }
 
@@ -271,7 +271,7 @@ class spell_gluth_decimate_damage : public SpellScript
 {
     PrepareSpellScript(spell_gluth_decimate_damage)
 
-    void RecalculateDamage()
+    void HandleDamage(SpellEffIndex /*effIndex*/)
     {
         Unit* target = GetHitUnit();
         if (!target)
@@ -291,7 +291,7 @@ class spell_gluth_decimate_damage : public SpellScript
 
     void Register() override
     {
-        OnHit += SpellHitFn(spell_gluth_decimate_damage::RecalculateDamage);
+        OnEffectHitTarget += SpellEffectFn(spell_gluth_decimate_damage::HandleDamage, EFFECT_0, SPELL_EFFECT_SCHOOL_DAMAGE);
     }
 };