I test it yesterday afternoon even fly it 1-3 ft, it hover right, it doesn't drop, i mean drop on 1ft flight and hit the ground, as it does before, after replacing the main gear and lube the bearing of the blade grip.
Baurwin you maybe right regarding lvc, as it did that to my heli long time ago, but it will drop only when the esc sence low voltage or if your battery is not charge, or after flying ater est 9 min of sport flying also depend on your battery mah and flying type.
Squawk7700, is your tail grounded, maybe it causing glitch on the tail. Some pilot grounding their tail even they are on 2.4 radio, check you tube regarding about it, as i did some research before about glitch causing heli to drop, it happen on mine last year.