Extracting closed planar curves from a parameter results in null values

In this example I have a number of closed planar curves feeding into a weave component.  I internalize the parameter on the component, and then extract it.  When the data consists of a closed planar curve the resultant extracted data tree has null values.  If the data consists of rectangles or circles I know this works.

Is this a bug somewhere, or is there something unique about the data extraction and closed planar curves that results in null results?