Error message in Pebbles Grasshopper plugin on Mac

I added the Pebbles for Grasshopper plugin on my mac (Rhino7) and loaded the example file provided by the developer. All of the examples don’t work due to this message on the visualizer component: Solution exception:Type ‘CoreGraphics.CGColor’ in Assembly ‘Xamarin.Mac, Version=0.0.0.0, Culture=neutral, PublicKeyToken=84e04ff9cfb79065’ is not marked as serializable.

Anyone knoe what this means or how to fix?
Pebbles Example Files. V.1.gh (48.7 KB)