could be it bigger drones are less affected but i think it is a mix of elements. it was pretty cold and really humid as it was a thick fog. So after a while the whole propeller was covered with ice, so there was no angle for it to generate lift.

the same also happened few years ago, but i didn't see the ice and thought it was just a weird malfunction. and i was pretty stressed out seeing it hitting the ground and bouncing. now i was more or less ok with what ever would happen, as it already survived more than i thought it will :)