I guess BOAC meant the fact that the A/T does no longer provide min speed reversion below 27ft RA and instead goes into landing retard mode. Which is exactly what happened to those THY guys because the left RA showed below 27ft.
On the NG i haven't had the A/T cutting in smooth air when flown at the correct speeds, however in gusty weather it is quite common and usually solved by a simple click on the disconnect button.