Nginx custom access log does not rotate

Question

I have configured a custom log in html section of nginx.conf:

        log_format jsonlog escape=json '{ "time": "$time_iso8601", '
                '"remote_addr": "$remote_addr", '
                '"remote_user": "$remote_user", '
                '"ssl_protocol_cipher": "$ssl_protocol/$ssl_cipher", '
                '"body_bytes_sent": "$body_bytes_sent", '
                '"request_time": "$request_time", '
                '"status": "$status", '
                '"request": "$request", '
                '"request_method": "$request_method", '
                '"http_referrer": "$http_referer", '
                '"http_x_forwarded_for": "$http_x_forwarded_for", '
                '"http_cf_ray": "$http_cf_ray", '
                '"host": "$host", '
                '"server_name": "$server_name", '
                '"upstream_address": "$upstream_addr", '
                '"upstream_status": "$upstream_status", '
                '"upstream_response_time": "$upstream_response_time", '
                '"upstream_response_length": "$upstream_response_length", '
                '"upstream_cache_status": "$upstream_cache_status", '
                '"http_user_agent": "$http_user_agent" }';

        access_log /var/log/nginx/json.access.log jsonlog;
        access_log /var/log/nginx/access.log;
        error_log /var/log/nginx/error.log;

While access.log and error.log rotate, json.access.log doesn't.

This is my nginx logrotate configuration (/etc/logrotate.d/nginx):

/var/log/nginx/*.log {
        daily
        missingok
        rotate 14
        compress
        delaycompress
        notifempty
        create 0644 www-data adm
        sharedscripts
        prerotate
                if [ -d /etc/logrotate.d/httpd-prerotate ]; then \
                        run-parts /etc/logrotate.d/httpd-prerotate; \
                fi \
        endscript
        postrotate
                invoke-rc.d nginx rotate >/dev/null 2>&1
        endscript
}

I think that this logrotate configuration is not applied to my custom log because the log file is created with root group instead of adm (as specified in create 0644 www-data adm):

-rw-r--r-- 1 www-data adm   28316313 30 mar 09.10 access.log
-rw-r--r-- 1 www-data adm   79362122 30 mar 00.00 access.log.1
...
-rw-r--r-- 1 www-data root 141300465 30 mar 09.10 json.access.log

What did I do wrong?

UPDATE

I've tried to force rotation with sudo /usr/sbin/logrotate -f /etc/logrotate.d/nginx and it has worked fine, and also the group is now correct:

-rw-r--r-- 1 www-data adm    10237 30 mar 14.59 json.access.log
-rw-r--r-- 1 www-data adm    90410 30 mar 14.59 json.access.log.1
-rw-r--r-- 1 www-data root 5767548 30 mar 14.58 json.access.log.2.gz

Let's see if tomorrow it will be rotated automatically...