Do not see Domain Mapping on one of the site inside Multisite.

So I can see Domain mapping on the admin site, and all sites in my multisite except one. My main one. I don't remember if it was never there or if it disappeared. Its resolving correctly to the site in question http://rescueonedog.com/

But I am not sure why domain mapping is not in the tools? Was it ever there? Should I be worried?