I posted this a little while back, but was unable to resolve the
problem, so keeping my fingers crossed that other have some insight...
Some percentage of users are unable to login as it appears the rails
session ID changes at each request. Note: these users do have cookies
turned on - though it behaves as if they do not. I tried moving the
session store from file based to active record based, but I am not
convinced this fixes the problem as this does not prevent the ID from
changing. One thing I did find was that when I changed the env from
pound balancing behind three processes to a single mongrel process in
the front, the problem disappears.