Tire Bubble problems of the 2011 Ford F-350

I have a 2011 Ford f350 that came with michelin ltx a/t2 - lt275/65r 20 tires. It has just over 28,000 miles, has only been serviced by a Ford dealer, with each service report indicating no problems with respect to tire issues. Traveling on the freeway I experienced a shaking in the front end like a wheel had thrown a weight. Pulling off the road I discovered a tread separation bubble approximately 12-13" long on the outer portion of a front tire. After changing to the spare we continued that day's driving. The next drive in the truck was towing our 5th wheel home and I again experienced the same shaking. I pulled over again and found the other front tire had separated in the same manner and size bubble. The two separations occurred within 300 miles of each other. It was only my recognition of the vibrations in the steering wheel that alerted me to pull over to inspect the tires before they blew out catastrophically. A catastrophic tire failure under normal circumstances is difficult enough, but while towing is an imminently greater hazard. I found the closest Ford dealership and had to purchase two new tires to get home. Once there I went to my Ford dealer and told them I wanted the other two tires off the truck before they failed. They have contacted michelin on my behalf and as yet I have not heard back from them, although it's only been a week. I hope michelin steps up and replaces all four tires. The only other piece of information that may be a contributing factor is that although the tires are warranted for 60,000k miles, they were worn to (7/32-5/32-10/32) on the bubble, 180 degrees (7/32-5/32-9/32) on one tire and (8/32-7/32-10/32) and 180 degrees across (10/32-7/32-10/32) on the other. I filed this report because I see that michelin has had a very similar problem with their ltx m/s2 tire and has or is conducting a voluntary recall. This tire is so similar to the a/t that I have to wonder if it's just a different tread pattern on the same tire carcass.