At first I also experienced some 'not very logic' behaviour of the wipers when on intermittent. It does not use a time interval, but the camera is used to decide whether the windscreen has any droplets on it. You can change the sensitivity by setting the ring on the wiper stalk. That can change things for the better.
Other things that might influence it:
- is the sensor (camera behind mirror on windscreen) clean?
- is the solar angle very odd, so that the camera might be blinded?
- did you recently go into a car wash that added a wax layer onto your car? I had to remove that layer because the wipers would not function properly at all (not only on intermittent): stripes, glare, whitish look
In very slow traffic, I sometimes just put the wipers OFF and manually press the stalk up to just do one wipe. At higher speeds intermittent is usually quite okay.
Good luck!