2015 Sonata bumper cover loose at rear wheel!
 

I noticed that the rear bumper cover just behind my passenger side wheel is loose. I can move it back and forth. I replaced one of the two retaining nuts/clips that holds the inner fender liner in place, but when I move the b-cover, the liner just slides back and forth with it. The retaining nuts aren't doing it's job. Has anyone had this issue before? Does anyone have any input to fix this?

So you put new retaining nuts/clips in
Did you put in a new bolt to lock the two parts together??

The stud was spot welded by the factory, all you have to do is push the new plastic nut until it stops clicking.

Sorry, can't help you.
On my 2001 Elantra, the rust was so bad that those spots where it is held together were almost gone.
I simply put epoxy steel on it and smoothed it out.
Then put nuts and bolts through that to keep the rear bumper to the fender.
Doesn't look great. But, it works.

Wish you luck on finding a fix

Thanks anyways! I might try something like liquid nail to keep it from shifting back and forth!