I've got that too. Noticed it last night. No way am I returning it though, it's a non-issue.Mine isn't loose, but the button bevel has a noticeable edge to it that my finger catches on. Does yours?
What the ****. No life much?The button on my 6 felt loose at one point but after searching around for others that had the same problem I got a fix for it. You need to get something like a baby wipe and make sure that it is only damp and not wet. Then just wrap the wipe around your finger and rub it across the home button in all directions making sure to get right into the home button. Then wipe it with a dry cloth and turn the phone over and tap it on something face down obviously in a case. I used my Air 2 Smart Cover to tap it on. You have to tap it fairly hard.
That was a fix for my 6 and the button on it is still perfect, it sounds and feels the same as the buttons on my Audi. The button on my 6s feels nowhere near as good so I tried the same thing with it and it made it better but not as good as my 6 or my Air 2(which I did it too as well)
Ope this helps.