Well if it's not coming from the sphere  you might be getting reflection from sunlight off the body itself.  Try a render where the camera is looking slightly down on the points of intrest instead of slightly up to it - if the shinyness goes away chances are the OBJs material mapping is allowing some metaliic or glassy shinyness. You could do a study with metalic spheres with different camera angles(HI/LO) and check the results to verify this.

I've also noticed sunlight angles in Bryce never seem exactly right. You have to compensate by moving the sun until the lighing is what you want.