Steps to reproduce:

1. Open the attached project GTKNodes
2. Open the graph under Editor/New Graph.simpleg
3. Open the script Editor/SequencerNode.cs
4. Change the node's inherited type from Node to ContextNode
5. Switch to the editor to view the New Graph.simpleg graph
6. Observe the already existing SequencerNode and create a new one next to it to see the difference

Note: changing the node's inherited type also results in this error:

NullReferenceException: Object reference not set to an instance of an object
Unity.GraphToolkit.Editor.Implementation.GraphModelImp.OnEnable () (at ./Library/PackageCache/com.unity.graphtoolkit@516997d56518/GraphToolkitPublic/Implementation/GraphModelImp.cs:46)
Unity.GraphToolkit.Editor.GraphObject.OnEnable () (at ./Library/PackageCache/com.unity.graphtoolkit@516997d56518/GraphToolkitEditor/Model/GraphObject.cs:350)
Unity.GraphToolkit.Editor.Implementation.GraphObjectImp.OnEnable () (at ./Library/PackageCache/com.unity.graphtoolkit@516997d56518/GraphToolkitPublic/Implementation/GraphObjectImp.cs:52)

Actual results: The note stays the same despite having a different structure

Expected results: The node should be refreshed/clearly invalidated

Reproducible with versions: 0.1.0-exp.1 (6000.2.0a9), 0.4.0-exp.1 (6000.3.0b3)
Tested on (OS): Windows 11