The groundspoiler bypassvalve is mechanical linked to a sensor on RH main LDG. It could very vell be, the same sensor that gives input to Air/Ground system.
So if this sensor is jammed by the (faulty) open valve, LDG Lever Lock Out solenoid will not open, due to A/G system logic, and gear lever cannot move up.
I could be wrong, but it seems like logic to me.
BTW: My QRH rev. is dated June 08, 2001. Says nothing about the new note
