Well, I've had many hundreds of out of signal range waypoint missions, with only a few problems. One got lost completely, but DJI replaced it for free because it was in warranty. Two I had in Thailand hit thin guy wires holding up a high...
I was flying a series of out of signal range waypoint missions over train track and terminals under construction near my house. I was on my 8th iteration of these missions. The 7th flight was fine. Then the next flight, 8, the drone did not...