I also fly the 777, I turn that junk off with the AP - pretty sure BA only put the recommendation (not requirement) in the manual on the advice of lawyers.

Pretty sure it's just selecting reverse which disconnects it since most who leave it on pilot override it in gusty conditions when in flight.

In the Global...we turn the A/T's system on as we cross the hold short line and ask for the below the line items of the Before T/O Checklist.
We are able to leave them on through landing if the PF prefers. They retard to idle when an RA of 50ft is reached.

Many people have many techniques...but one for sure consistent one is to have them off in gusty winds. Too much chasing plus and munis speed changes.

YMMV

Cheers to that. . Its actually Idle while landing manually. It wouldn't be in IDLE unless in the flair. Throttles are in SPD until that time. Somewhere between 50-25 ft. I guess I didn't make it clear. But it doesn't matter. You'll get power one way or the other if you need it.

Book says "if the thrust levers are overridden during a manual landing, after the autothrottle has begun to retard the thrust levers to idle"