This might have the same reason as this recent post: A too strict firewall that doesn’t allow the info-beamer updater access to the required server. The result is that the updater cannot function. As the updater is also used for every configuration change, the same applies to the configuration editor: Applying changes also won’t work.
That’s expected: info-beamer OS itself used the first two 96MB partitions. The third partition fills the rest of the SD card and is used for assigned data.
This too hints at a firewall/network issued. Can you check the four colored icons in the bottom right corner of the welcome screen? Are they all lit up green?