All my cars have done this. I'm at 4400ish and starting to see it.
My issue is (same with my 2009 Focus I bought brand new) my seat cushion is starting to creak. So if bounce a bit from a bump I hear a creak creak like old wooden floors or squeaky rocking chair or squeaky rubber bushing.
It's nowhere as bad as the noise my 09 made but this will get annoying soon enough.
Glad they fixed it under warranty and I'm assuming they'll do the same for me this time.
The thing that gets me is, I'm not even fat or anything.. lol
I'm about 5'10" and 150-160lbs
1965 Mustang Coupe 289 4spd
2003 Land Rover Discovery II SE
2013 Lincoln MKZ Hybrid