I've tried many different combinations of settings, but it seems that the action of capturing an image is only triggered when there is a change from "no motion" to "motion". If there is continuous motion, then additional images are not captured.
For example, open the Motion Detection window and watch the top horizontal bar below the motion preview window. When motion is below the tolerance threshold, the bar is green. when motion is above the tolerance threshold, the bar is red. Set Image Array to 2 images at 1000 ms and deactivate Flood Control. With these settings, I would expect to get 2 images at one second apart as soon as motion is detected. If the motion continues longer than two seconds, I would expect to get another two images one second apart and so on until the motion stops.
That is not what happens. I get two images one second apart, but then I don't get any additional images until the motion stops and restarts. The top horizontal bar has to go back to green and then to red again before the next images are captured.
Try continuously waving your hand in front of the camera. Notice that images will not continue to be captured until you stop moving your hand and then restart moving your hand.