I haven't come across this problem in Carrara, but haven't really done much with refraction. That said, in RayDream, if you had a refractive object in front of a refractive object, the foreground object's refraction would prevail, eliminating the refraction of the background object. This may be related to that effect. You might work around that by rendering scene without the glass in it, set that render as your backdrop, then render the glass with everything else invisible and with an alpha channel. Do a third render of the entire scene and composite all of them together and photoshop the hell out of it to get the reflections of the cherries and such all to work out. Not a pretty solution, but it would work. Hope that's helpful. It's an awesome model; the texture for the glass tabletop is awesome! - Dex