Just double checked - both parent and child theme behave exactly the same i.e 4 footer columns with no sidebar and 3 with sidebar.
Are you calling the functions.js from the child theme?
One thing I've notice is that Jetpack kind of messes up the site flow in local servers but is ok on live servers - so I'm guessing there might a slight chance that a plugin is interfering somewhere somehow if you are on a local server.