I'm beginning to think they all have this issue but people do not hear it. Driving last night it is all I could hear over the damn frost heaves in my area. I asked my wife who was in the passenger seat (never told her about this issue) if she heard it... radio off, HVAC off, just listen.. and she says (it's the tires hitting the bumps.
Told her no, you shouldn't hear thuds over and over when hitting bumps. So 8,300 miles, she does not hear it, I do. I never noticed it sooner because the radio is loud enough to overcome it.