Zend Framework Session swapping issue

I'm helping develop a website based on Zend Framework which has begun to experience session swapping issues that appea开发者_如何学JAVAr at random. WE have found no way of detecting this issue except when our users and ourselves experience session swaps when refreshing or navigating the site. we have found no order or pattern to help us determine what the cause is. Our system uses two database, standard website database and an API database. We have noticed that the cron jobs for these two database create a large number of sessions except this should not cause a session swapping issue with the number of occurrences we have experienced.

We are attempting to discover some way of detecting the cause of this issue. We would appreciate any tips or advice on how to find the cause of this issue. Any advice would be greatly appreciated.

UPDATE: we have development and testing subdomains which have never had the session swapping occur there. it seems it only occurs on the live production website.