It certainly wouldn't be the first time they tested a feature to later implement it as additional content.
EDIT: Also they added this:
They add an information menù with an update list, that means that we get a lot of updates in next months probably... Otherwise will be useless.
The 1.26 update is about 3,7 GB, so now I have a new mission: use the glitched save to catch new things in Cartanica... Maybe this 3,7 GB isn't all about the the new content as they had announced, like the past updates, maybe there's hidden stuff.
(why Cartanica? Because they trying to fix this map adding hidden content in last updates, like new roads and building)