So hear me out here.

What if the next patch launches the new dungeon immediately and it's into the 13th for an expedition.

We fight our way through 3 bosses, using Estinien, Y'shtola, and king (who will flex roll) only to run head long into Golbez, who reveals the missing dragon is his now and is a shadow dragon.

In an attempt to save our lives we are forbidden from going back, cutting off the storyline into 13th immediately.

My point here, is it is way too early to really tell as they can easily be doing this as a misdirect.