I saw a recent version of cPanel that used ngnix as a proxy in front of Apache, with Apache on a high port. That might be responsible for a lot of the new ngnix seen out there.
cPanel has no native support for nginx, if you've seen that it's been using a third party plugin. The second most popluar server controlpanel Plesk supports the configuraion you describes bt it's not enabled by default so I doubt will be affected the statistics.
