Sudden unexplained acceleration incident. Car accelerated without input from driver and rear-ended a parked vehicle in front of the vehicle Eyesight system did not engage to warn or prevent impact with rear end of car in front. The vehicle was travelling at low speed and suddenly accelerated. This is dangerous because it does not provide enough time to prevent from hitting an object in front of the vehicle like a car or person. The problem has not been reproduced by by the manufacturer who sent a technician who inspected the vehicle and could not find any saved info in the event data recorder or saved diagnostics codes. Complaints were filed with the dealership before the incident that the eyesight system did not appear to be functioning correctly. The first time this has happened was 6/02/2021 in the afternoon on a clear day on a clear pathway without any obstructions. The second time this happened was 9/06/2021. The second incident the vehicle accelerated while travelling at lo speed with the eyesight system briefly warning tone beeping. The brakes were applied quickly and the carr seemed almost to stall. The engine made a noise as the stalling conditions ended and the car went back to normal. Subaru filed a service request previously. SR# 1-70302162357.