Network options on a GameObject where the GameObject is a prefab instance will only be serialized if the values differ from the prefabs. When loading a prefab instance as a GameObject from a Hammer scene, find the correct network mode. This fixes an issue where if a prefab is added via Hammer, but later the prefab's network mode or something changes, the new default wouldn't be used when loading the map. It'll still use the one the map was serialized with.