72blu is correct. Just picked up a couple of like new used Michelins for my daughters Toyota and was told anything after 2020 they call "rubber butter" It's getting worse, now they are softer and age faster so watch it and watch out!
That's kinda what I was getting at. I don't have any evidence of it other than my memory. I guess even stating that is "fear mongering". My bad. Do you have any evidence of it? I have my suspicions, but I don't know for sure.
