Core/Vehicle: Fix an assertion when applying SPELL_AURA_SET_VEHICLE_ID on creatures that are already vehicles (#30102)

(cherry picked from commit 53f0f2e5da3e7e6a9e6fa926e2f51ac8b506caa9)

2 files changed, 9 insertions, 3 deletions

diff --git a/src/server/game/Entities/Vehicle/Vehicle.cpp b/src/server/game/Entities/Vehicle/Vehicle.cpp
index f68486d7439..0b8b3b20af5 100644
--- a/src/server/game/Entities/Vehicle/Vehicle.cpp
+++ b/src/server/game/Entities/Vehicle/Vehicle.cpp
@@ -52,7 +52,7 @@ UsableSeatNum(0), _me(unit), _vehicleInfo(vehInfo), _creatureEntry(creatureEntry
     // Set or remove correct flags based on available seats. Will overwrite db data (if wrong).
     if (UsableSeatNum)
         _me->SetNpcFlag((_me->GetTypeId() == TYPEID_PLAYER ? UNIT_NPC_FLAG_PLAYER_VEHICLE : UNIT_NPC_FLAG_SPELLCLICK));
-    else
+    else if (!unit->m_unitData->InteractSpellID)
         _me->RemoveNpcFlag((_me->GetTypeId() == TYPEID_PLAYER ? UNIT_NPC_FLAG_PLAYER_VEHICLE : UNIT_NPC_FLAG_SPELLCLICK));
 
     InitMovementInfoForBase();
diff --git a/src/server/game/Spells/Auras/SpellAuraEffects.cpp b/src/server/game/Spells/Auras/SpellAuraEffects.cpp
index 5be5832e743..22d9e258f64 100644
--- a/src/server/game/Spells/Auras/SpellAuraEffects.cpp
+++ b/src/server/game/Spells/Auras/SpellAuraEffects.cpp
@@ -5371,13 +5371,19 @@ void AuraEffect::HandleAuraSetVehicle(AuraApplication const* aurApp, uint8 mode,
 
     uint32 vehicleId = GetMiscValue();
 
+    target->RemoveVehicleKit();
+
     if (apply)
     {
         if (!target->CreateVehicleKit(vehicleId, 0))
             return;
     }
-    else if (target->GetVehicleKit())
-        target->RemoveVehicleKit();
+    else
+    {
+        if (Creature* creature = target->ToCreature())
+            if (uint32 originalVehicleId = creature->GetCreatureTemplate()->VehicleId)
+                creature->CreateVehicleKit(originalVehicleId, creature->GetEntry());
+    }
 
     if (target->GetTypeId() != TYPEID_PLAYER)
         return;