Occasionally when saving a SW2009 drawing file as either a DWG or DXF (I've tried both ways) one or more curves in the drawing will end up as a series of tiny, self intersecting loops rather than a smooth curve as drawn in SW.

I've tried opening the files in AutoCAD and Illustrator (and a few others) and DWG file is indeed NOT the same as the SW file.

I can't find rhyme or reason to the problem: sometimes all is well, then the next very similar part when saved as a DWG will have a particular curve segment that when zoomed in on, will be self intersecting curves instead of one smooth curve.

Any ideas what's going on?