logging to syslog

Hello,

I'm trying to setup logging to syslog by following the instructions here;
https://www.nginx.com/resources/admin-guide/logging-and-monitoring/

The issue i'm hitting is that if i throw in say, this line
access_log syslog:server=our.syslog.server,facility=local7,tag=nginx,severity=warn;

It'll just log it to a log file named "our.syslog.server,facility=local7,tag=nginx,severity=warn" in /usr/share/nginx . Which will eventually grow and consume all the disk space on the server.
It does this whether I try to log to an external syslog server or the systems syslog. Can anyone point me to what i'm doing wrong?

Thanks!