Print SCP not working

[ATSandrearicci]

The exception thrown is:
Cannot cast to 'Image'; type must be assignable from 'byte[]'
From row 52 of var frame = image.RenderImage().As(); In ImageBoxExtensions.cs

To reproduce it just download sample, run Print SCP and run Print SCU from Windows Visual Studio using .Net Framework 4.x
I tried also with .Net 8.0, same error.