Hello,
It seems like I have another bug to report. I hope its not a repost.
There is a difference in the image when working with the final render compared to the IPR. It appears that when geometry is a bit troubled (but still works fine in the viewport / final render) the IPR just looses its cool. :)
Generally what appears to be happening is that some materials just produce odd reflections and they don't respect some of the material parameters like glossiness etc...
It very much looks like a phong issue to me.
Attached is the screenshot and the file has been submitted through the helpdesk.
Again, I hope its not a repost :)
Thanks!
edit: The IPR is on the right, the final frame on the left.