Red and Green Flashing Traffic Light

So, on my way home tonight, I noticed a traffic light near my home was flashing red and green, alternately. In the past, traffic lights I’ve seen that were malfunctioning either flashed red or yellow, or were off altogether. So, was it just screwed up, or is there some significance I’m ignorant of? My mind keeps going back to that joke about driving through the intersection by hitting the gas, then the brake, then the gas, etc. For the record, I stopped before I went through.