I reported this to Brian about a year ago on the Yahoo group (was also broken when I was in G41/G42 mode) and it's been worked on by him. It did get fixed a few versions back (3.043.057 as per the change log), but I still see it here now and again (ver 062 here), but not sure why sometimes it works and other not. I did notice that it goes hand in hand with another problem where the toolpath window doesn't highlight the cut path. These both appear or disappear together. And it can happen in the same session with the same gcode - one part it runs OK, then the next it doesn't.
Dan