Caching Static Assets Issue

[jeremib]

WPT is complaining of errors in my caching, it's complaining that my assets do not have an expires or max-age tag, when in fact they do:

Test Results: http://www.webpagetest.org/result/130404...ic_content

When I look at a specific asset:

$ curl -I http://cdn.follybeach.com/wp-content/the.../style.css
HTTP/1.0 200 OK
Content-Type: text/css
Content-Length: 28056
Connection: keep-alive
Date: Mon, 11 Mar 2013 20:04:03 GMT
Server: Apache/2.2.22
Last-Modified: Mon, 11 Mar 2013 19:05:28 GMT
ETag: "6d98-4d7aadb34afee"
Accept-Ranges: bytes
Cache-Control: max-age=31536000, public, must-revalidate, proxy-revalidate
Expires: Tue, 11 Mar 2014 20:04:03 GMT
Pragma: public
X-Powered-By: W3 Total Cache/0.9.2.7
Age: 2072534
Vary: Accept-Encoding
Via: 1.0 fb114910c8a204ba2e239f3b94b7bab5.cloudfront.net (CloudFront)
X-Cache: Hit from cloudfront
X-Amz-Cf-Id: _yX6JvbSVqmktz6JlWD3IFfgv5fFmL6XfPzsELImnh0m1ZW2UjZyNQ==

$ curl -I http://www.follybeach.com/wp-content/the.../style.css
HTTP/1.1 200 OK
Accept-Ranges: bytes
Cache-Control: max-age=31536000
Cache-Control: max-age=31536000, public
Content-length: 28110
Content-Type: text/css
Date: Thu, 04 Apr 2013 19:52:35 GMT
Expires: Fri, 04 Apr 2014 19:52:35 GMT
Last-Modified: Fri, 29 Mar 2013 01:33:16 GMT
Pragma: public
Server: nginx
Vary: Accept-Encoding
Connection: keep-alive

Any help would be appreciated in resolving this.

[pmeenan]

I'm not sure if it's explicitly what I detected but must-revalidate effectively disables the browser cache and forces the browser to always check with the server to make sure the version it has is current.