Amazon is a retailer, they aren't responsible for providing warranty.
I asked on email Asus, Gigabyte, Asrock and Sapphire regarding 2 warranty on Amazon and this was there similar answer:
"Warranty is given by seller and it cannot be extended by anyone else. If you want to have full 3 years warranty, please found other seller who will provide full 3 years warranty period."
So if I buy mbo or gpu from Amazon I will have only 2 years of warranty.
Amazon does NOT provide warranties.
https://www.amazon.com/gp/help/customer/display.html?nodeId=468516
?? I think that Amazon gives 2 years on their stuff. IF something happen to my gpu I send it to Amazon...