outline artifacts on shapes without strokes at lowered opacity

above is a (fill-only) shape at 30% opacity, but this happens at any opacity even with outlined text.  this anomoly does show up in exports.  I've already found a workaround, but it would be better if the adobe team can address the issue to prevent it.  In the appearance window, even though the parameters for stroke color and weight are empty, if you toggle visibility of the stroke the artifacts will go away.