Previous updates would only have the extra content be present in the phone section as pictures and small scenes, and not as a fully playable storyline in the game itself.
So not sure why they paywalled almost half or more of the update behind the extra pack as DLC, it was never mentioned leading up to the release of the update either, I think.

Most of us just assumed it was a bug at first, and I don't think they have commented on the change yet either.
But my guess would be they either wanted to make the extra pack have more value to it or to make up for the huge amount of revenue they lost out on to people dropping their subscriptions due to the delays we keep getting hit by.
Very unfortunate timing of them to introduce it now too, since a few people have already started talking about them possibly milking the game with the delays in order to get more payments (their words not mine).