So far I've been lucky. Every few days my hexa is falling from the sky, but always managed to land it with minimal damage. My new retractable landing gear seems to work as a dampener as well.
Remember, this is the same hexa which is also twitching, the thread about the twitching is here:
I replaced the cables, added some ferrite rings and I concluded that the twitching can get worse or better by changing different PID values. For example changing the Throttle Rate P from 6 to 4.2-4.5 makes it twitch less in Stabilized mode.
Anyway, this tread is about the question - why is this falling out from the sky randomly? See the below video when I captured this on film.
The logs for this flight are attached, falling happened toward the end of the flight about 2-3 minutes before the end. The Hexa was loitering pretty well, and I switched back from loiter to stabilized, it was still flying for a second or two - then fell out from the sky. The firmware version is 2.8.1