How to reproduce:

1. Import the attached package
2. Open VFX
3. Open AllProperties SG
4. In the Blackboard, select TotalCount SamplerStater Matrix4x4 properties
5. Using the shortcut delete, delete them
6. Save the graph
7. Undo action
8. Save the graph

Note: if it is not reproducible from the first time, keep repeating 4-8 steps

Another note: this seems only to happen with ShaderGraph that are converted from old Integration to new Integration

Reproduced on 23.1.0a10

Few lines from the stacktrace:

{color:#0747a6}0x00007FFB3998E61B (Unity) VFXMemorySerializer::StoreObjects{color}
{color:#0747a6}0x00007FFB3998E883 (Unity) VFXMemorySerializerBindings::StoreObjectsToByteArray{color}
{color:#0747a6}0x00007FFB37A1673E (Unity) VFXMemorySerializer_CUSTOM_StoreObjectsToByteArray{color}
{color:#0747a6}0x000001BB40FA1A05 (Mono JIT Code) (wrapper managed-to-native) UnityEditor.VFX.VFXMemorySerializer:StoreObjectsToByteArray{color}