Go with GY "H" tries the only failure I have heard of with a GY "H" is the one Rusty just mentioned. Rusty can confirm or deny but I believe GY paid for a new tire and the damages. I only buy Michelins for my TV's and had excellent performance but for the RV it's GY since they will pay when not a road hazard. I for sure use the 75MPH rating of the GY tires when traveling in the 75mph speed limit states.
Op I would bet your Michelin tire was a recipient of something that punctured the tire.