diff --git a/src/server/game/Entities/Creature/Creature.cpp b/src/server/game/Entities/Creature/Creature.cpp
index 918e889b5..841f42d5a 100644
--- a/src/server/game/Entities/Creature/Creature.cpp
+++ b/src/server/game/Entities/Creature/Creature.cpp
@@ -2580,20 +2580,26 @@ void Creature::SetInCombatWithZone()
 void Creature::ProhibitSpellSchool(SpellSchoolMask idSchoolMask, uint32 unTimeMs)
 {
     for (uint8 i = SPELL_SCHOOL_NORMAL; i < MAX_SPELL_SCHOOL; ++i)
+    {
         if (idSchoolMask & (1 << i))
+        {
             m_ProhibitSchoolTime[i] = World::GetGameTimeMS() + unTimeMs;
+        }
+    }
 }
 
 bool Creature::IsSpellProhibited(SpellSchoolMask idSchoolMask) const
 {
-    const CreatureTemplate* cinfo = GetCreatureTemplate();
-    if (!(cinfo && cinfo->flags_extra & CREATURE_FLAG_EXTRA_ALL_DIMINISH) && (isWorldBoss() || IsDungeonBoss()))
-        return false;
-
     for (uint8 i = SPELL_SCHOOL_NORMAL; i < MAX_SPELL_SCHOOL; ++i)
+    {
         if (idSchoolMask & (1 << i))
+        {
             if (m_ProhibitSchoolTime[i] >= World::GetGameTimeMS())
+            {
                 return true;
+            }
+        }
+    }
 
     return false;
 }