See the link to see the images. Seems it exploded in transit. User's claim is, upon opening the box, found this.
iPhone 7: Exploding Apple iPhone 7 shown in photos | BGR
iPhone 7: Exploding Apple iPhone 7 shown in photos | BGR
Yes I see an exploded phone, but take a careful look at the packaging. You can clearly see there was damage to the box that obviously transferred to the phone inside most likely causing this.
I would take this with a grain of salt, if there was a serious issue, the global press would be all over it.