I guess the market is getting used to its delay (this is the third time) and this time it provides a definite time table to deliver.
Boeing's plan was to outsource almost all major manufacturing to outside companies and then assemble the plane in Everett. It has since found that such a decentralized structure makes it hard to keep a check on suppliers' mistakes and delays.
The latest delay means Boeing will have to compensate airlines for late deliveries, but it hasn't put any figures on how much that could cost.