2D/3D Bezier with Bevel Object

Does anyone know why simply switching on/off the 3D toggle for a Bezier curve Blender changes the way the bevel object is applied? The capture below shows identical Beziers, each with the same bevel object curve applied. But one has the 3D toggle activated and you can see the difference.


The blend file is here: http://www.skwerm.com/blender/2D3D_Bevel.blend

Thanks for any help with this!

that is a strange effect…i guess you need to have the 3d option off…are you using it to prevent filling of the curve?