"No max-age or expires" for images that already have expire headers

This is my test result: http://www.webpagetest.org/result/160226_RD_6JG/1/performance_optimization/#cache_static_content

There are several images that are flagged as “No max-age or expires” for example this one:

FAILED - (No max-age or expires) - http://image.ttg-static.net/izaya-kankin-durarara-arabic-yamato-asaisai_45097774b31a4eaba6800a1baccba347.jpg

However, when I inspect the headers, both the max-age and expires headers are available, for example, this is the result for url http://image.ttg-static.net/izaya-kankin-durarara-arabic-yamato-asaisai_45097774b31a4eaba6800a1baccba347.jpg using online tool http://www.webconfs.com/http-header-check.php:

HTTP/1.1 200 OK => Date => Fri, 26 Feb 2016 03:46:58 GMT Content-Type => image/jpeg Content-Length => 38149 Connection => close Set-Cookie => __cfduid=d9ce05fab0e3e4af966ec17e9417d2bd11456458418; expires=Sat, 25-Feb-17 03:46:58 GMT; path=/; domain=.ttg-static.net; HttpOnly Cache-Control => public, max-age=2592000000 Last-Modified => Thu, 18 Feb 2016 15:21:37 GMT ETag => "5691c3004dfff8e62cef562b41c9d1a7" X-Cache => Hit from cloudfront Via => 1.1 b08d3fd1ea7c0f4b62f5adbb976ab099.cloudfront.net (CloudFront) X-Amz-Cf-Id => sei9Ms9ZN-0uzOyFPNsHRsxJGbO_wuoT-dyiAq09b5vvp5hIE0h5YQ== CF-Cache-Status => HIT Expires => Wed, 16 Apr 2098 03:46:58 GMT Accept-Ranges => bytes Server => cloudflare-nginx CF-RAY => 27a8aa78a97d2a13-SEA

This photo is stored in S3 server by Cloudfront and then shielded by Cloudflare, so the requests looks like this

I also read the question carefully from the thread http://www.webpagetest.org/forums/showthread.php?tid=14209 but it seems to be a diffrent problem. Please help!