Box2D moving kinematic bodies move dynamic body with them even if they have no contact at all

Question

I am writing a platformer game (like Mario). My player is a dynamic body, platforms are kinematic. I apply impulse in -X direction on all kinematic platforms, to organize the scroll of platforms. But they start to move with them the dynamic body - the player too. I thought it is because of the friction. But the strange thing is that they move player even if player is in air jumping and have no contact with them at all. Why?

Answer 1

This was because I didn't set density to my dynamic body, so it was moving by inertia after the first touch with the kinematic bodies.