Port From (https://github.com/TrinityCore/TrinityCore)

Core/Spells: Removed duplicated check
Revert "Core/Groups: fix wrong query for loading group instance data. canReset attribute was calculated in the wrong way"
Core/Scripts: moved Wild Growth calculation to script and fixed formula

Source/Game/Groups/GroupManager.cs

@@ -182,10 +182,12 @@ namespace Game.Groups
             {
                 uint oldMSTime = Time.GetMSTime();
 
-                //                                                0           1        2              3             4             5            6           7
-                SQLResult result = DB.Characters.Query("SELECT gi.guid, i.map, gi.instance, gi.permanent, i.difficulty, i.resettime, i.entranceId, COUNT(g.guid) " +
-                    "FROM group_instance gi INNER JOIN instance i ON gi.instance = i.id " +
-                    "LEFT JOIN character_instance ci LEFT JOIN groups g ON g.leaderGuid = ci.guid ON ci.instance = gi.instance AND ci.permanent = 1 GROUP BY gi.instance ORDER BY gi.guid");
+                //                                                 0       1       2            3            4             5            6
+                SQLResult result = DB.Characters.Query("SELECT gi.guid, i.map, gi.instance, gi.permanent, i.difficulty, i.resettime, i.entranceId, " +
+                    //           7
+                    "(SELECT COUNT(1) FROM character_instance ci LEFT JOIN groups g ON ci.guid = g.leaderGuid WHERE ci.instance = gi.instance AND ci.permanent = 1 LIMIT 1) " +
+                    "FROM group_instance gi LEFT JOIN instance i ON gi.instance = i.id ORDER BY guid");
+
                 if (result.IsEmpty())
                 {
                     Log.outInfo(LogFilter.ServerLoading, "Loaded 0 group-instance saves. DB table `group_instance` is empty!");
@@ -210,7 +212,7 @@ namespace Game.Groups
                     if (difficultyEntry == null || difficultyEntry.InstanceType != mapEntry.InstanceType)
                         continue;
 
-                    InstanceSave save = Global.InstanceSaveMgr.AddInstanceSave(mapEntry.Id, result.Read<uint>(2), (Difficulty)diff, result.Read<uint>(5), result.Read<uint>(6), result.Read<ulong>(7) != 0, true);
+                    InstanceSave save = Global.InstanceSaveMgr.AddInstanceSave(mapEntry.Id, result.Read<uint>(2), (Difficulty)diff, result.Read<uint>(5), result.Read<uint>(6), result.Read<ulong>(7) == 0, true);
                     group.BindToInstance(save, result.Read<bool>(3), true);
                     ++count;
                 }

Source/Game/Spells/Auras/AuraEffect.cs

@@ -5690,19 +5690,6 @@ namespace Game.Spells
             }
             else
             {
-                // Wild Growth = amount + (6 - 2*doneTicks) * ticks* amount / 100
-                if (m_spellInfo.SpellFamilyName == SpellFamilyNames.Druid && m_spellInfo.SpellFamilyFlags & new FlagArray128(0, 0x04000000, 0, 0))
-                {
-                    int addition = (int)((damage * GetTotalTicks()) * ((6 - (2 * (GetTickNumber() - 1))) / 100));
-
-                    // Item - Druid T10 Restoration 2P Bonus
-                    AuraEffect aurEff = caster.GetAuraEffect(70658, 0);
-                    if (aurEff != null)
-                        // divided by 50 instead of 100 because calculated as for every 2 tick
-                        addition += Math.Abs((addition * aurEff.GetAmount()) / 50);
-
-                    damage += addition;
-                }
                 if (isAreaAura)
                     damage = (int)(caster.SpellHealingBonusDone(target, GetSpellInfo(), (uint)damage, DamageEffectType.DOT, GetSpellEffectInfo(), GetBase().GetStackAmount()) * caster.SpellHealingPctDone(target, m_spellInfo));
                 damage = (int)target.SpellHealingBonusTaken(caster, GetSpellInfo(), (uint)damage, DamageEffectType.DOT, GetSpellEffectInfo(), GetBase().GetStackAmount());

Source/Game/Spells/SpellEffects.cs

@@ -2447,12 +2447,9 @@ namespace Game.Spells
             if (effectHandleMode != SpellEffectHandleMode.HitTarget)
                 return;
 
-            if (unitTarget == null)
-                return;
-
             // this effect use before aura Taunt apply for prevent taunt already attacking target
             // for spell as marked "non effective at already attacking target"
-            if (!unitTarget.CanHaveThreatList() || unitTarget.GetVictim() == m_caster)
+            if (unitTarget == null || !unitTarget.CanHaveThreatList() || unitTarget.GetVictim() == m_caster)
             {
                 SendCastResult(SpellCastResult.DontReport);
                 return;

Source/Scripts/Spells/Druid.cs

@@ -55,6 +55,7 @@ namespace Scripts.Spells.Druid
         public const uint LivingSeedProc = 48504;
         public const uint MoonfireDamage = 164812;
         public const uint RejuvenationT10Proc = 70691;
+        public const uint RestorationT102PBonus = 70658;
         public const uint SavageRoar = 62071;
         public const uint StampedeBearRank1 = 81016;
         public const uint StampedeCatRank1 = 81021;
@@ -1045,4 +1046,38 @@ namespace Scripts.Spells.Druid
 
         List<WorldObject> _targets;
     }
+
+    [Script]
+    class spell_dru_wild_growth_AuraScript : AuraScript
+    {
+        public override bool Validate(SpellInfo spellInfo)
+        {
+            return ValidateSpellInfo(SpellIds.RestorationT102PBonus);
+        }
+
+        void HandleTickUpdate(AuraEffect aurEff)
+        {
+            Unit caster = GetCaster();
+            if (!caster)
+                return;
+
+            // calculate from base damage, not from aurEff->GetAmount() (already modified)
+            float damage = caster.CalculateSpellDamage(GetUnitOwner(), GetSpellInfo(), aurEff.GetEffIndex());
+
+            // Wild Growth = first tick gains a 6% bonus, reduced by 2% each tick
+            float reduction = 2.0f;
+            AuraEffect bonus = caster.GetAuraEffect(SpellIds.RestorationT102PBonus, 0);
+            if (bonus != null)
+                reduction -= MathFunctions.CalculatePct(reduction, bonus.GetAmount());
+            reduction *= (aurEff.GetTickNumber() - 1);
+
+            MathFunctions.AddPct(ref damage, 6.0f - reduction);
+            aurEff.SetAmount((int)damage);
+        }
+
+        public override void Register()
+        {
+            OnEffectUpdatePeriodic.Add(new EffectUpdatePeriodicHandler(HandleTickUpdate, 0, AuraType.PeriodicHeal));
+        }
+    }
 }