Honestly with the millions of tires produced every year for so many different vehicles, things do just happen to tires sometimes. Also it's always possible that even if you don't think you ever hit anything, objects that are really hard to see can be sticking up in the pavement and cut the sidewall of a tire as a vehicle passes, causing a failure. I haven't heard anything specific to those tires recently. A few years back the Goodyear tire failures were posted a few times on here.
I've worked in the tire business for 15+ years now, kinda see it from every tire brand out there. If there is legitimate concerns with batches of tires, they do send out recalls and have stop sales when it happens. The LT tires are under more stress with higher tire pressures, checking for sidewall damage, and ripples or bubbles should be done more often. Exactly why pre-trip inspections are required for Class A/B trucking and anything DOT related.