the attached Rhino file has two simple extrusions in it. One has a brazil glass material applied to it, the other a plastic material. In the Neon screenshot, you can see the plastic behind the glass. In the Brazil rendering you cannot see it.
Can anyone tell me what's going on here?
It's rendering as expected here. Do you actually have raytraced refraction turned on, it looks like it's not, but again if I open up your file and render it works.
Edge softening is applied to the extrusion - there seems to be a bug with this at the moment in Rhino. We'll get it looked into.
Yup - it is a bug in SR0 Rhino 5. It should be fixed in SR1 - which is why it works on Jim's machine (he's presumably running the release candidate)