Core/Scripts: fixed npc immunity flags during Harbinger Skyriss encounter

- Added missing _Reset
- Properly register Skyriss summons in SummonList

Closes #21154

Who ordered up an extra large can of whoop-ass?

(cherry picked from commit f8b148c3346e6d5017bf3b044cc36bce32c0cf45)

2 files changed, 11 insertions, 3 deletions

diff --git a/src/server/scripts/Outland/TempestKeep/arcatraz/arcatraz.cpp b/src/server/scripts/Outland/TempestKeep/arcatraz/arcatraz.cpp
index cc7397d6f26..3dd69ae1c1d 100644
--- a/src/server/scripts/Outland/TempestKeep/arcatraz/arcatraz.cpp
+++ b/src/server/scripts/Outland/TempestKeep/arcatraz/arcatraz.cpp
@@ -106,7 +106,10 @@ class npc_millhouse_manastorm : public CreatureScript
                 Initialize();
 
                 if (instance->GetData(DATA_WARDEN_2) == DONE)
+                {
                     Init = true;
+                    me->SetImmuneToNPC(false);
+                }
 
                 if (instance->GetBossState(DATA_HARBINGER_SKYRISS) == DONE)
                     Talk(SAY_COMPLETE);
@@ -178,6 +181,7 @@ class npc_millhouse_manastorm : public CreatureScript
                             case 7:
                                 instance->SetData(DATA_WARDEN_2, DONE);
                                 Init = true;
+                                me->SetImmuneToNPC(false);
                                 break;
                             }
                             ++Phase;
diff --git a/src/server/scripts/Outland/TempestKeep/arcatraz/boss_harbinger_skyriss.cpp b/src/server/scripts/Outland/TempestKeep/arcatraz/boss_harbinger_skyriss.cpp
index 9b840bf3c6c..4c543f5301a 100644
--- a/src/server/scripts/Outland/TempestKeep/arcatraz/boss_harbinger_skyriss.cpp
+++ b/src/server/scripts/Outland/TempestKeep/arcatraz/boss_harbinger_skyriss.cpp
@@ -98,9 +98,9 @@ class boss_harbinger_skyriss : public CreatureScript
 
             void Reset() override
             {
-                if (!Intro)
-                    me->SetImmuneToPC(true);
+                _Reset();
 
+                me->SetImmuneToAll(!Intro);
                 Initialize();
             }
 
@@ -131,6 +131,9 @@ class boss_harbinger_skyriss : public CreatureScript
                 if (me->GetVictim())
                     if (Unit* target = SelectTarget(SELECT_TARGET_RANDOM, 0))
                         summon->AI()->AttackStart(target);
+
+                summons.Summon(summon);
+                summon->SetImmuneToAll(false);
             }
 
             void KilledUnit(Unit* victim) override
@@ -182,7 +185,7 @@ class boss_harbinger_skyriss : public CreatureScript
                             Intro_Timer = 3000;
                             break;
                         case 3:
-                            me->SetImmuneToPC(false);
+                            me->SetImmuneToAll(false);
                             Intro = true;
                             break;
                         }
@@ -286,6 +289,7 @@ class boss_harbinger_skyriss_illusion : public CreatureScript
 
             void Reset() override
             {
+                me->SetImmuneToPC(false);
                 me->RemoveUnitFlag(UNIT_FLAG_NON_ATTACKABLE);
             }