coopster - 9:31 pm on Jan 20, 2013 (gmt 0)
I don't use APC myself, so I really cannot offer any insight. Would the request still show in the Apache logs? And is it? If so, is there anything in the request/response headers that may be enlightening? I'm thinking along the lines of eTag, If-Modified-Since, etc. and the other cache-associated header requests and responses.