Those pictures are old, according to the dates on them, and not all the same tires. And we have no idea how old the tires are and what their history is. So not sure what the point is.
The O.P. definitely had an issue. Personally I think it was a bad manufacturing run of tires. It shouldn't have happened, but probably did to others who purchased the same run of tire. I would like to think that Michelin identified the issue and fixed it, but who knows. If there was a recall, would you get a full replacement, or just a pro-rated replacement like he did?