I hope it's nonsense, as I have tickets for Sunday. But it wouldn't be unprecedented to begin previews with an unfinished show. As I remember it, The Lion King, when it was out of town, started previews with an unfinished 2nd act.
Aida in Atlanta, with its famous malfunctioning pyramid set, would often perform the show in a concert version.
Tom Sawyer, out of town, discovered that it's Broadway sets wouldn't fit into their theatre, so they performed there without the set.
By the way, I have a friend of a friend in the show, who says it's going to be amaaaaazing...but that it might take a while to get through it on Sunday.
Behind the fake tinsel of Broadway is real tinsel.