surf() plot renders incorrectly

[Terry Duell]

Hello All,
I am running Octave 3.6.4, from Fedora repo, on Fedora 18 x86_64, and  
Gnuplot 4.6.1-4, also from Fedora repo.
Data plotted using gnuplot and surf() is rendered incorrectly, from some  
viewpoints.
If I rotate the surface the rendering may be corrected, but may appear  
again at another viewpoint.
If I use fltk, the rendering appears to be correct, but I am unable to  
rotate the surface in the fltk window, so it is difficult to properly  
check.
The attached files "surfprof3.m" and "surfacedat.txt" illustrate the issue.
If you look at the gnuplot surface plot, at approx (1,90,12.5) you will  
see the incorrect rendering of the surface, at the edge. Compare that with  
the fltk surface plot.
Is this a gnuplot bug?

Is it expected that a surface rendered by fltk is able to be rotated  
within the window?

Cheers,
--
Regards,
Terry Duell

surfprof3.m
Description: Binary data

surfacedat.txt
Description: Text document