Why does my Wordpress Child Theme say it has an update?

I had a child theme created by a freelancer from Elance.  However, I don't understand why an update alert is showing on my Child Theme - I thought that the parent theme would show update alert.  That same freelancer told me to just switch to parent and update parent then switch back.  Is this correct? When I update the child theme I lose my customizations so I'm sure that you are not suppose to update a child theme - just the parent.  However, why is the child theme even showing an update when I made it?

Thanks in advance for your replies.