In some cases, desynchronization occurs, and the item created on the server and attached via AddChild to the machine is not displayed on the client, causing significant freezes (lags) on the client. At the same time, the item may be displayed on many clients, but on some client where desynchronization has occurred, the item is not displayed. This can be fixed by deleting the item attached via AddChild and spawning the item again.

Object m_AnyObj= g_Game.CreateObject("MyChildObj" "0 0 0");
CarScript m_Transport = GetTransportOnServer();
m_Transport.AddChild(m_AnyObj, -1, false);