Issue with caching cookies

["Rafael Mahnovetsky" <rafael.mahnovetsky@xxxxxxxxxxxxxxxx>]

Hey Guys

I'm having an issue with my website where a user will sometimes be switched to someone else's session. Tracing this down it is because they have been given another users cookie. After searching through the logs I was able to narrow the issue to Apache. 

I have apache setup with mem cache and proxy load balancer with 4 mongrel's server (those that don't know ruby on rails server). With this set up I was able to find a bug that was close to my description (
http://issues.apache.org/bugzilla/show_bug.cgi?id=42935). The answer was to add this line CacheIgnoreHeaders Set-Cookie. Though the issue still exists.   

I have searched the net and I can't find anything else on the subject. Does anyone know what could be the issue? Could Apache still be caching the cookies? 

below mem cache setup

<IfModule mem_cache>
  CacheEnable mem /
  MCacheSize 16000
  MCacheMaxObjectCount 500
  MCacheMinObjectSize 1
  MCacheMaxObjectSize 3048
  CacheDisable /accounts/
  CacheIgnoreHeaders Set-Cookie
</IfModule>