I have been using Arnold a while now but just can't figure this one issue out. I have built a simple scene to illustrate the issue clearly. Basically I have built an empty drinking glass and behind it I have a robe, and then there is just a background with studio lighting setup. But for some reason I cannot see the robe though the glass.
I imported the official Ai shader from Arnold's website for glass, and I have made sure the glass object has the opaque setting turned off under the Arnold tab. Also I have set my Ray Depth Refraction to 6, and have checked that my normals are facing outwards. What else could be causing this effect?