On the 787 disconnecting the Autothrottle is a separate action from disconecting the A/P. You may already be doing this but after rereading your OP it occurred to me that this is a separate key bind. I have a button on my throttle lever bound to disconnect A/T, perhaps you have this too? When hand flying the Dreamliner on approach, it helps to leave the A/T engaged, and only disengaging it just before touchdown (or leaving it for the automation to do that). Nice to have options!