The factory bars had a bad resonance at 60-70 MPH and iirc were fitted with dampeners.
I wonder if these suffer the same...

I remember my first wagon with cross bars, Both JimmyL and I condemned the rear differential when we heard the noise. Later, I discovered it was coming from the bars. I had moved the front one up closer to the sunroof opening to haul a load of lumber.
It was obvious with the sunroof open.