The link above doesn't seem to work for me, but I received my recall letter today.
The letter is headed "I-Shift transmission Software Error", which would imply a software-upgrade only is required, but then the letter goes on to talk about an apparent mechanical issue, so I'm not sure.
The letter says "A part of the reverse gear selector mechanism may become mis-aligned if the vehicle is repeatedly parked in reverse gear on a hill. If the mechanism is mis-aligned, it may be possible for the reverse gear to stay engaged even when neutral is selected. This may cause the vehicle to move backwards unexpectedly even if the gauge displays "N" when the engine is running and may lead to an accident or personal injury. "