Steps to reproduce:

1. Create a new project using Universal 3D template
2. In the Project window, right-click -> Create -> Shader Graph -> URP -> Lit Shader Graph
3.  Open the Shader Graph, right-click -> Create Node -> Matrix 2x2
4. Right-click -> Create Node -> Custom Function
5. Select the "Custom Function" Node and in Graph Inspector add a new list item to the "Inputs" list
6. Change the property type to "Matrix 2"
7. Connect the "Matrix 2x2" Node to "Custom Function" Node
8. On the "Custom Function", change the created "Input" property type to anything else (e.g., Vector 2)
9. Observe the Node

Actual results: No error is shown after the type change; the mismatch error only appears after a graph refresh (e.g., adding another node)

Expected results: The Node immediately reports a type mismatch (e.g., “Concretization: Slot <InputName> cannot accept input of type <Type>”) whenever the connected types are incompatible, regardless of prior valid connections

Reproducible with versions: 6000.0.69f1, 6000.3.10f1, 6000.4.0b11, 6000.5.0a8

Tested on (OS): Ubuntu 24.04, macOS 26.2

Notes:

• Saving the graph has no effect; only reopening the graph or creating another node surfaces the error
• If you change the property type again to another incompatible type, the error disappears until the next refresh