Jagged curves created with the variable stroke width tool?

I know this is ultra nit pickey, but I'm very detail oriented and I use the stroke width tool all the time, so this bothers me quite a bit.

In Illustrator CS6 and CC, when the stroke width tool is used on a curve, the curve is actually made up of a series of straight lines instead of smooth vector curves:

whereas in CS5 it looks perfect:

These images may be too small to see the details, but the difference is there. Is there a workaround for this? Or is it recognized as a bug? CC is mostly great, but this one thing is super frustrating.

Thanks!