Right, at the last step (if you checked-in more than 24 hours before the flight), you'll told you need to wait until 24 hours before the flight to request a boarding pass. Then at the 24 hour mark, it doesn't give you the option to get a mobile boarding pass.

In the past, I've encountered bugs where I have been issued a mobile boarding pass, but then I'm forced to get a paper pass to actually board the plane. Good thing they have printers at the gate!