Rendering difference v7 file in v8

I have a duct transition object created in FWplus (v7 file) by joining two 2d shapes together (rectangle and a circle)

When viewed and shaded in v7 in looks as it should when viewing the file in v8 the rectangular end becomes rounded in anything other than wireframe.

Converting the file to v8 did not help the situation.

Has anyone come across this before?

 

I just created a 3d PDF of the file and the PDF file got it right. Luxology rendering renders it properly.

I also meshed the item and then it appeared properly in v8.

A curiosity at this point. 

I am on SS3 on a 64bit Windows 7 system with Nvidia Quadro K600 (updated driver) if anyone is interested in looking into it.