I don't have an option for Wide Polylines, just Polylines, and when I use it my pads get Filled and there is no outer border line around the pad. The pads appear black on my drawing and it's distracting. Not a disaster, just not what I'm used to.
Since you asked, it would be nice if the pads in Polyline mode had an outline so I could ditch the fill. ; )
For DXF Export with Outlines only (no fill) please select Entity Output: "MERGE (Outline Only).
Note: If problems persist please submit a support ticket so we may help directly, and if possible please let us know what version you are using. I believe you may have an older version which does not have the option "Wide Polyline" as I suggested.