What is a Traffic Camera doing when it is Flashing--or shuttering--nonstop?

Having made my approach to an intersection with a red light, at speed limit, in a sunny afternoon, I stopped before the crosswalk and gazed up at the traffic camera mounted above as I waited for the light to transition to green. I noted that the area around its lens flashed, or shuttered, incessantly for about 8 seconds--likely longer, but the light turned green--although it could only be noticed by looking directly at it. My question is whether this is common behavior--given the interval, no photo-enforced red light cameras in the vicinity, and the absence of malpractice on my part--of the traffic camera or if it was registering an infraction? To describe the situation further, a car was to my right (but also didn't appear to do anything out of the ordinary).