Phalcon, Redirects and Nginx

Hey there,

I began switching to nginx just recently and use an application I developed with Phalcon to test how the migration works. I now ran into a problem with redirects from phalcon which result in an 502 error from ngix which logs the following in my errorlog:

upstream sent invalid status "Redirect" while reading response header from upstream

This happens always when I'm redirecting in my code, i.e. for instance calling /admin would redirect you to /session/login if you're not logged in:

$this->response->redirect("session/login");

Other actions which don't redirect you work just fine. Querying google as to what might be the problem didn't really help, but I might have searched for the wrong things as nginx is still new to me.

Can anyone point me to the right direction please? :)

P.S.: Since someone might ask, this is my nginx config for the host in use:

server {

    listen   80;
    server_name domain.dev;

    index index.php index.html index.htm;
    set $root_path '/var/www/project/public';
    root $root_path;

    location / {
        try_files $uri $uri/ /index.php?_url=$uri&$args;
    }

    location ~ \.php$ {
            try_files $uri =404;
            fastcgi_split_path_info ^(.+\.php)(/.+)$;
            fastcgi_pass unix:/var/run/php5-fpm.sock;
            fastcgi_index index.php;
            fastcgi_param  SCRIPT_FILENAME  $document_root$fastcgi_script_name;
            include fastcgi_params;
    }

    location ~* ^/(css|img|js|flv|swf|download)/(.+)$ {
        root $root_path;
    }

    location ~ /\.ht {
        deny all;
    }
}