If you want the latest content to be loaded from the latest symlinked release using PHP Deployer you need to add these lines to your Nginx PHP block
fastcgi_param SCRIPT_FILENAME $realpath_root$fastcgi_script_name;
fastcgi_param DOCUMENT_ROOT $realpath_root;
After doing this you do need to reload Nginx one time. But once done you will never need to reload PHP FPM to see the latest PHP changes due to older symlinked content being loaded still.