I had problems with my 2 year old Coker Clasics about 8 years ago, they cracked around sidewall at the bead . After some back and forth they replaced them, did not want to replace the spare as it did not show any problems (never been on the road)I had to pay the shipping of the bad tires to them and they paid the shipping of the replacments to me.
No problems with the replacments after 8 years so I guess they fixed whatever was wrong in the manfacturing process 10 years ago.
In the end they stood behind the product and did also replace the spare as it was in the same date code range as the others.