You're using a global variable, ::remove_lbsession to track when to delete the cookie. Global variables are accessible for all requests, so this may lead to trampling of the value and unexpected results. I'd suggest first changing the rule to use a local variable. I wouldn't use the RULE_INIT event at all. You can set a local copy of the variable in the HTTP_REQUEST event using 'set remove_lbsession 0' and then update it to 1 if the request is for the logout page.
If you're still seeing unexpected results, add logging in the HTTP_REQUEST event to see if the client is presenting the cookie after you've tried to expire it.
Aaron
Nimbostratus
