Did some runs today and tried the single 5200LiHv packs (really have to learn how to make screenshots with the moverio). Took me a bit over 11.300m (37.000') (@50m alt.) out and cause the wind had picked up since last run came 600m short on return
I can also confirm that when the critical battery mode was reached the mavic's yaw became ridiculously sensitive and hard to control. I found a spot between some apple trees and made a nice soft landing. By the time I got there some guy with dog was holding my precious in his hands about to walk off. Although he claimed he didn't, I saw that he must have tried to disconnect the external battery by simply pulling the cables totally deforming the battery adapter leads..
Good thing you got there just in time. I wasn't so lucky when I lost my first Mavic. Long gone when I got there 10 minutes later. 37,000ft is very good. How far did you take it into auto landing mode? Did you take it all the way to 1%? I guess you did if you got the critical landing mode. Well that's not too bad if you only saw sensitive Yaw. On some of ours, we see that at 8% and lower the Mavic starts Yawing on it's own as the motors are not able to maintain stability. Mine basically fell out of the sky at 3%. You have the clip, which has a bit more resistance. With the direct mod, the sub-10% is even worse. Mine used to fly below 3% somewhat, but now it's only good to about 4%. Of course my overall run time is much better with the direct battery mod. It's only the last 10% that is more difficult to deal with.