Originally Posted by
ScepticalOptomist
The FMC on the 787 is more like the old Pegasus FMC on the 767 - in many ways a step backwards from the FMC on the 737 NG.
It may well be running that FMC as a virtual machine, which would explain a lot (not least as to why it assumes that it has the aerodynamics of an AGA when it comes to descent planning).
I also believe that it should fly to either the UP speed or the green flap speed shown on the PFD when in the intermediate stages of the approach with the speed window closed. It’s an easy thing to miss given that it will close itself when you activate VNAV.