The contact owns a 2024 Tesla Cybertruck. The contact stated while driving 49 MPH with the Full Self-Driving (FSD) activated, the destination was entered, and the system announced the direction steps and suddenly the Full Self-Driving (FSD) disengaged independently causing the driver to be required to take control of the vehicle. During the independent disengagement of the Full Self-Driving (FSD), the vehicle abruptly accelerated and almost struck another vehicle in a head-on collision. The contact was concerned that the failure could result in a crash if other vehicles were in the opposite direction. On a separate occasion, the contact stated that the Full Self-Driving (FSD) was engaged and driving at various speeds, and the vehicle independently maneuvered into oncoming traffic on a 2-lane road causing the contact to have to take control of the vehicle. A crash was avoided; however, the contact was concerned that if there had been a median barrier it could have resulted in a crash. In addition, the contact stated there was a second occasion where the vehicle was in Full Self-Driving (FSD) and veered into oncoming traffic, and manual control of the vehicle was required. The failure was not recorded via the Tesla App. A dealer was contacted, and a service appointment was scheduled for a diagnostic test. The Tesla Service Advisor informed the contact that there was nothing in the systems logs that there was an error, and the dealer was not able to duplicate the failure. The vehicle was not diagnosed or repaired. The manufacturer was notified of the failure several times. The failure mileage was approximately 2,000.