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I managed to fix it! 

It was a server configuration issue (PageSpeed (bitnami) to be specific).

I tail -fed the access log and saw 

xxx.my.ip.xxx - - .... "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_8_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/32.0.1700.102 Safari/537.36"

xxx.server.ip.xxx - - .... "Serf/1.1.0 mod_pagespeed/1.6.29.2-"


Figured out definitely something is wrong with server (why is it hitting twice!).

Disabled and it worked fine

# Include conf/pagespeed.conf
# Include conf/pagespeed_libraries.conf


This issue was not happening in the dev site maybe because I have apache basic http authentication enabled (hence pagespeed was not caching it, just guessing).