I have same terrain asset in PlayScene and NetWorkScene in my project. When Terrain is selected in Hierarchy / Inspector and NetworkScene is reloaded to PlayScene errors and assert fails.

To repro:
1. Open NetworkScene.
2. Select Terrain in Hierarchy.
3. Press Play.
4. Press LAN Host.

Actual result: PlayScene is loaded. Assertion and errors are in log.

MissingReferenceException: The object of type 'Terrain' has been destroyed but you are still trying to access it.
Your script should either check if it is null or you should not destroy the object.
UnityEditor.TerrainInspector.OnSceneGUICallback (UnityEditor.SceneView sceneView) (at /Users/builduser/buildslave/unity/build/Editor/Mono/TerrainEditor/TerrainInspector.cs:1796)
UnityEditor.SceneView.CallOnSceneGUI () (at /Users/builduser/buildslave/unity/build/Editor/Mono/SceneView/SceneView.cs:2371)
UnityEditor.SceneView.HandleSelectionAndOnSceneGUI () (at /Users/builduser/buildslave/unity/build/Editor/Mono/SceneView/SceneView.cs:1699)
UnityEditor.SceneView.OnGUI () (at /Users/builduser/buildslave/unity/build/Editor/Mono/SceneView/SceneView.cs:1536)
System.Reflection.MonoMethod.Invoke (System.Object obj, BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) (at /Users/builduser/buildslave/mono/build/mcs/class/corlib/System.Reflection/MonoMethod.cs:222)

'Assertion failed on expression: 'srcAttach < m_CurrentFramebuffer.colorCount && "We should always resolve only current RT"' '
is getting spammed in the console window.

MissingReferenceException: The object of type 'Transform' has been destroyed but you are still trying to access it.
Your script should either check if it is null or you should not destroy the object.
UnityEngine.Transform.get_position () (at /Users/builduser/buildslave/unity/build/artifacts/generated/common/runtime/TransformBindings.gen.cs:26)
CompleteProject.CameraFollowNew.FixedUpdate () (at Assets/CameraFollowNew.cs:33)

Expected result: No errors in log.

Regression since 5.6, does not repro in Version 5.5.0f3 (38b4efef76f0)
Thu, 24 Nov 2016 13:54:18 GMT
Branch: 5.5/release