OS Matcher Issue

I am trying to use the Class, smart-class matcher “OS” and can’t seem to figure out what it’s looking for to make it work right (apply class parameters).

I’ve searched and found discussions on the topic and it mentions "what Foreman shows under OS’s name or the hosts “OS” as listed BY foreman. In this case its “CentOS Linux 7.4.1708” which I’ve tried and doesn’t work. Also tried just CentOS and other variations.

WHAT is it looking at to match or not match this?

So, fiddling around with is more it does match “CentOS 7.4.1708”. The “Linux” portion was added to description and muddied the waters confusing me.

Using just the CentOS X.X seems to work, sorry for the spam.