If i select a pline and open the properties palette, there is a property in the Misc group named "Linetype generation" that can be either enabled or disabled. What function does this provide? What is linetype generation?
With PLINEGEN set to 0, the linetypes of polylines are generated independantly for each segment of the polyline, for arc segments this means that the linetype will always be generated in an anti-clockwise direction, which for some linetypes can be a problem.
With PLINEGEN set to 1, the linetypes of polylines are generated continuously along the entire polyline, in this case arc segments that are drawn in a clockwise direction will have the correct linetype orientation.
One draw back of having plinegen set to 1 is that if a shape or text falls at the end of a segment it can be projected outside the line of the polyline.
The attached image shows the effect of plinegen when used with linetype containing text. The top polyline has Linetype Generation disabled, the bottom enabled.
Somewhere in the back of my mind i suspected it had something to do with linetypes that contain words and i even ran a couple *simple* tests using the GAS linetype you used in your example. But my tests didn't expose the answer. In fact, i didn't even know the var was PLINEGEN.