So I was going to help with:
When I started to make my response I noticed that if you reference a ray picked meshes material and then try to set the cullBackFaces it says that that property does not exist, yet when you console log out the material and can see the property in the objects context…
The plot thickens even more that you can console log out the specific material that the pick is supposedly referencing (the actual declared reference not the pick reference) and the cullBackFaces is there no problem…
This is really funky behavior.
See lines 67,68
more pair of eyes usually help