Extra lines showing when in rendered settings

Im having an issue where extra lines that shouldn’t be visible appear when I put a detail view into rendered setting. These dont appear when in shaded or anything else. Ive played around with the render settings to no luck. Is it something to do with my graphics card? Ive attached any image below showing the view in shaded and rendered.

Hi Shape -

Please post both the .3dm file and the output from the Rhino SystemInfo command.
-wim