It is a design flaw. In the bottom half of the crossbar holder is a capture nut. It is round and sits in a round housing. When you try to tighten or loosen the bolt in the top half, there is nothing to keep the capture nut from spinning. My dealer just swapped out crossbars f
from a truck on the lot.
So it is fixed on 2016 models? I am not sure tightening that bolt would help it grip much better. I ended up putting a bolt through bracket and bar. When I slide bar to back, I'll fill the holes with rubber plug.
Yeah, I wish I hadn't put the holes in. But I was 100km from home, and 300km from destination, and I only had a drill and 2 1/2" self tapping metal screw. Different scenario, and I may have come up with a more elegant solution.