It's definitely odd that you're getting routed across the country to an east coast pop. Ideally in your location you'd be routed to a west or central pop. Perhaps a bad combination of Cloudfront getting geolocation wrong for your IP range, and poor performance of at&t's network for that specific source-destination combination.
I found that odd as well, and my iPhone hotspot does get routed through a different list of hosts as you can see in the traceroute.
I suppose it should be noted. The iphone antenna and router antennas are no more than a meter from each other. They're unlikely to be hitting different towers.
