Urgent: Session drops in rails 2.3.2

Hello, I've been using memcache as a session store. After updating to rails 2.3.2, I've started encountering site users' sessions being dropped. This affects only the servers where the new rails is deployed. These session dropouts are intermittent and seem to increase with the number of requests to the rails application. This only occurs in production and works fine in development and test environments (using active_record as a session store in these envs). We're using the following setup in production: Apache 2.2.6 with Phusion Passenger 2.1.3 (also tried with passenger 2.2.2 but to no avail)

This is how I'm setting up memcache session store in production.rb:

# MEMCACHED_SERVERS holds array of memcached servers ips (total 3)
MEMCACHED_OPTIONS = {:namespace => "myapp-#{RAILS_ENV}"}
CACHE = MemCache.new MEMCACHED_SERVERS, MEMCACHED_OPTIONS
config.action_controller.session_store = :mem_cache_store
config.action_controller.session = {:cache => CACHE}

I've tried looking through the rails/rack codebase, but haven't figured out why this is happening.

It would really help if someone can look into this and at the least, inform me whether this is a rails 2.3.2 bug or something on my end. Thanks, Ali