Bevel has undesired offset

[foulowl]

Followed the tutorial here:
http://www.iearobotics.com/blog/2012/09/13/enhancing-openscad-ii-bevel-library/

Noticed a bit of visual tearing along the edge of the bevel. Changed to front view, orthogonal and zoomed in, saw this:
http://i.imgur.com/AEYRS1x.png

The offset looks minor, but of course with designing parts you don't want to have issues like this, you want your models to be clean.

OpenSCAD 2014.03.

Thank you!