Plesk Panel Nginx issue with vhost_nginx.conf

[Balles]

Hello,

I have two plesk servers and when I go through the Panel and add lines to Nginx configuration and save Web Server Configuration, the panel doesn't include this line in last_nginx.conf:
include "/var/www/vhosts/system/DOMAIN.COM/conf/vhost_nginx.conf";

I need to execute manually:
/usr/local/psa/admin/sbin/httpdmng --reconfigure-domain DOMAIN.COM

With this command the include line returns to last_nginx.conf

Servers OS:
CentOS 6.5 (Final)
CentOS 5.10 (Final)

Plesk Panel version:
Plesk 11.5.30 #31

Thank you