Can you go to your car and check if both cross bar is stiff with no movement ?

On my rear bar both sides it can move a little bit, while the 2 **** holder is tight on the side rails
I found 2 screws under each but I wanted to know if the play is there to allow for expansion

I found it odd that both sides have about the same play. But if only one side was loose I probably won't feel any play

See the picture it is the 2 torx threaded from the bottom up

 

Well I took a torx bit to it and sure enough the rear bar bolts were completely loose.
I made a tool by using a tiny vise grip to hold a t25 bit
I layed a towel in the work area as to not scratch the paint since the space is tight.

I just snugged the bolt and the play in the bar is gone.
I read somewhere you don't want to really crank it down and I think they are just set screws

I did both bars 8 bolt total to make sure they are at least a little past hand tight

So if your bar rattles or is loose this is at least a temporary fix and something to check regularly

 

Just checked. Rock solid