Thanks. This is for a site in development - redhare.com. I opted to just embed the slider into a marginless section, and it works just fine. I would like to know the fix anyway, though, in case I ever want to put a slider above the masthead in the future. I've made this work on another site (melissac.rocks) without issue, so I am stuck on this one.
I have redhare.com secured behind the Under Construction plugin, and the site is hardened with iThemes. I will send login in a private message.