I had a problem I got out about 4k feet with my M2-Z and my drone thankfully stopped. I it the RTH button and it came back.....had me freaked a bit..The caveat here is I was in way points with litchi app. When this occured I was under the impression that it was flying off waypoints and my only limit was to how much battery life I have. this is the first failure i have had with litchi.. I have not tried DJI waypoint function yet.. can any one add to this post ??