Yes, even after the patient has been successfully defibrillated, they are still at risk of developing ventricular fibrillation again. The AED will continually monitor the victim for the return of VF. If VF is suspected, the device will prompt you. The AED should be left on until emergency personnel assume responsibility for the patient.
In some cases the victim may be hours away from advanced care so keeping a recently revived person calm and leaving the pads on is vital especially if there are not extra pads available.