Futureroads, you did well to cycle the remote, reconnect it and land it again. Just for future reference though, had you done nothing it would have landed at critical battery regardless of any obstacles. So if you were satisfied with where it was located at the time, another option would have been to sit on your hands. It does not fall out of the Sky at critical battery, It simply announces "Critical Battery Landing" at ~12%, descends and lands. If you end up in this state with RC actually connected (not your scenario), keep in mind, while you have no control over elevation & it descends regardless with left stick unresponsive, YOU STILL HAVE YAW so can fly it around obstacles which is most useful. This will allow you to fly maybe 50 yards laterally if it occurred when the Mavic is at 50' for example.
You seemingly had Low battery RTH triggered and most probably it sensed spurious obstacles. The log will divulge more no doubt. I am interested to see what others find although I don't have enough spare data to download it myself.