Strange indeed. One theory I found is that it's simply dust. Another theory that it's the paint burning:LOLThat's the burning remains from the container that kept the last remaining malaria mosquito in the world.BTW, where does that smoke/dust come from?
On the video it looks like it is some matter on the landing area which disperses as the rockets get closer.
BTW I thought maybe it is some chemicals intendedly spread over the landing area to cool down the rocket and/or prevent fire.