Fixed crashes and errors when loading into world.

Source/Game/Entities/GameObject/GameObject.cs

@@ -3559,7 +3559,7 @@ namespace Game.Entities
             uint _stateChangeProgress;
             List<uint> _stopFrames = new();
             bool _autoCycleBetweenStopFrames;
-            TimeTracker _positionUpdateTimer;
+            TimeTracker _positionUpdateTimer = new();
             List<WorldObject> _passengers = new();
 
             static TimeSpan PositionUpdateInterval = TimeSpan.FromMilliseconds(50);

Source/Game/Entities/Object/Update/UpdateField.cs

@@ -382,7 +382,7 @@ namespace Game.Entities
 
         public void ClearChangesMask<U>(OptionalUpdateField<U> updateField) where U : new()
         {
-            if (typeof(IHasChangesMask).IsAssignableFrom(typeof(U)))
+            if (typeof(IHasChangesMask).IsAssignableFrom(typeof(U)) && updateField.HasValue())
                 ((IHasChangesMask)updateField._value).ClearChangesMask();
         }
 

Source/Game/Entities/Object/WorldObject.cs

@@ -2981,9 +2981,9 @@ namespace Game.Entities
         public bool IsPermanentWorldObject() { return m_isWorldObject; }
 
         public ITransport GetTransport() { return m_transport; }
-        public T GetTransport<T>() where T : ITransport
+        public T GetTransport<T>() where T : class, ITransport
         {
-            return (T)m_transport;
+            return m_transport as T;
         }
         public float GetTransOffsetX() { return m_movementInfo.transport.pos.GetPositionX(); }
         public float GetTransOffsetY() { return m_movementInfo.transport.pos.GetPositionY(); }

Source/Game/Entities/Player/PlayerTaxi.cs

@@ -33,6 +33,8 @@ namespace Game.Entities
 
         public void InitTaxiNodesForLevel(Race race, Class chrClass, uint level)
         {
+            m_taximask = new byte[((CliDB.TaxiNodesStorage.GetNumRows() - 1) / 8) + 1];
+
             // class specific initial known nodes
             if (chrClass == Class.Deathknight)
             {
@@ -105,6 +107,8 @@ namespace Game.Entities
 
         public void LoadTaxiMask(string data)
         {
+            m_taximask = new byte[((CliDB.TaxiNodesStorage.GetNumRows() - 1) / 8) + 1];
+
             var split = new StringArray(data, ' ');
 
             int index = 0;