To the OP, yes! In Boeing FBW aircraft, a downgrade from Normal flight control mode will render the autopilots inop. I know of at least one incident where this occurred due to momentary unreliable airspeed, and the flight control mode could not be reset to Normal. I found a precis of the event here:
Serious incident Boeing 787-8 Dreamliner VH-VKE, Monday 21 December 2015