Experimental updates are enabled (although also happens when disabled), the scenario pack was already installed prior to the 0.12.23 update. It does not happen on a fresh 0.12.23 zip.
Log
You missed out on a great chance to use the version number "9.0.0.1" for the scenario pack...HanziQ wrote:Yes this is intended. The scenario pack content was moved into the base mod, this deletes the scenario pack, so the content doesn't show up twice. On a new install, you don't have scenario pack installed (the update that installs it was disabled), so this doesn't show up.