"Take Site Offline" and "Site off-line message" Options Won't Save

Hi everyone,

When creating a new Profile, I've tried to check the "Take site offline" box and type in new text for the "Site off-line message" (both under Advanced Options).

However, when I click "Save profile", those settings are not being saved. As a result, the old default settings are shown instead.

Any ideas on what could be causing this? Taking the site offline is pretty essential for us when doing scheduled backups.

Thanks,
Ben