That looks like it was struck by something and not like any of the cracking I've seen in person or pics shared online.
Keep us posted on the outcome of the claim, I am interested if Ford this.
No impacts that I am aware of. I assume an impact would also leave a scratch or other evidence.
Looks like my fears have come true. Noticed a crack on the passenger side rear. On closer inspection it’s worse than it first appeared and is cracked a good distance along the length of the seam. No initiating event. Never used a roof rack. Never removed the top.
Warranty claim is started...
Have you considered the Nokian Outpost? These come in 315/70/17, are a reasonable weight of 61.7 lbs, 3PMSF rated, load range F, and have a 60k mile warranty.
I recently bought a set of these for my Excursion and am very happy with them.