Steps to reproduce:

1. Import learning templates
2. Open MultiStripSingleBurst VFX
3. Change ShaderGraph output (Robot Pliers Mesh) to any other shader (e.g., SG_Baseball)
4. Convert output to Unlit Quad
5. Press CTRL/CMD + Z to undo all changes (without releasing keys)

Actual results: VFX is not rendered, some ports from SG Output disappear until recompiled and errors are spammed to the console

Reproducible with versions: 6000.0.33f1, 6000.2.0a5

Not reproducible with versions: n/a

Can’t test with versions: n/a

Tested on (OS): Windows

Notes:

Error 01:

ArgumentException: Context does not exist
UnityEditor.VFX.VFXData+<GetAttributesForContext>d__40.MoveNext () (at C:/../../Documents/unity/packages/com.unity.visualeffectgraph/Editor/Data/VFXData.cs:246)
System.Linq.Enumerable.Any[TSource] (System.Collections.Generic.IEnumerable`1[T] source, System.Func`2[T,TResult] predicate) (at <83c2e80c632943a485c1e12619e4eddd>:0)
UnityEditor.VFX.VFXBasicInitialize.GenerateErrors (UnityEditor.VFX.VFXErrorReporter report) (at C:/../../Documents/unity/packages/com.unity.visualeffectgraph/Editor/Models/Contexts/Implementations/VFXBasicInitialize.cs:136)

Error 02:

Unity cannot compile the VisualEffectAsset at path "Assets/Samples/Visual Effect Graph/17.0.3/Learning Templates/VFX/MultiStripSingleBurst.vfx" because of the following exception:
System.ArgumentNullException: Value cannot be null.
  at UnityEditor.VFX.VFXExpressionMapper.AddExpression (UnityEditor.VFX.VFXExpression exp, System.String name, System.Int32 id) [0x000df] in C:\..\..\Documents\unity\packages\com.unity.visualeffectgraph\Editor\Compiler\VFXExpressionMapper.cs:139 

I did not check whether it is a regression