OK, I had a very frustrating day yesterday trying to do offline mapping at a location that's about 3 hours away.
At first the mission icons displayed with the edit icon (pencil) and I had to start, restart, unplug, replug several times to get a ready (airplane) icon. I finally started a mission which worked just fine except that the aircraft only took 5 shots, then the camera faced forward and finished the mission without snapping any more pictures. After that I couldn't get a mission to fly and I kept getting the "cannot upload to a mobile device." message. So, I didn't get to test the end orbit because I wasn't able to get another mission to run.
Fortunately I had a competitor's app installed on my device and it worked flawlessly.
I really like so many things about DroneDeploy and it would be my first choice, but either its function is too obscure for my tiny brain to make it function or its very buggy.