So I went out to google groups and there seems to have been no resolution to this issue.

I used the instructions found here to setup NGINX / PHP-FPM using the dotdeb sources in Ubuntu:

http://www.howtoforge.com/installing-php-5.3-nginx-and-php-fpm-on-ubuntu-debian

I'm having tons of 502 errors randomly occur on requests. It's really bad -- to figure out how to avoid this problem we set it up the same way on another server -- same issue.

The only workaround I can figure out is to set a cron job to manually restart php-fpm every 5 minutes ... I'd like to not have to do that.

Let me know if there's some way of avoiding this issue...