The small Allen key adjuster for the brake lever position was set too close to the point where the magnet triggers the sensor so after a little use the lever does not move far enough away to clear the magnet from triggering the sensor.The brake light remains on and the bike has no PAS or throttle.Of course unplugging the switch opened the circuit and the bike would operate again.It can be either the RH or LH brake that is causing the problem.We have had several more reports of this fault and I expect that more will occur as the bikes are being ridden.
The cure is to use a 2mm Allen key and turn the small adjustment screw 2 or 3 turns clockwise which allows the brake lever to move further outwards so the magnet clears the sensor.