Curbed has a reasonably detailed construction update: "The structure has cleared its final architectural setback and has two frustum-shaped stacks left to pour. This final section will contain the skyscraper’s unoccupied blow-through floor, created to lessen wind loads and reduce building sway."
The developers also claim the glass didn't delay the schedule. We shall see!
https://chicago.curbed.com/2018/10/2...s-installation