Enduro

I've just noticed after a 40 minutes drive in the rain that there is a clicking noise coming from the driver's side windshield's wiper when it's on intermitten mode. It goes away after 2-3 wipes when i switch it to normal mode. Has anyone experienced this? Motor problem? Gear slipping? Not sure if I've had this problem for how long since this is the first time after a long drive that I got stuck in traffic that is slow enough to switch from normal to intermittent mode and to hear the small but audible noise. None of the search on the wiper topic produced desireable result.