I am unsure if this is new or it has never worked. We recently disabled s9e from taking Amazon and making it media tagged embeds so we just noticed it. Following is a list of different URL's we have tried.
Our site is fixing other URL's properly as far as I can tell like this recent one: http://money.cnn.com/2016/09/06/technology/weapons-of-math-destruction/index.html
I read an old post about Amazon having their title on their page deeper than 20kb and that there was a fix pushed to look for title up to 50kb. I edited the AutoLink.php file to look up to 100kb based on that post and there was no change. I didn't restart php-fm and I assume I didn't need to but let me know if I should try that.
Attached is what I have it set to in the ACP.