I have a new mini 2 and have been flying it with no issues using my android phone. But, today I chaged to using the IPad mini 4 because of the bigger screen. I got the message "mobile device fully loaded...." and I took off ok. But once the drone was about 100 meters away, the controls did not make the drone turn left or right and the compass on the screen showing where the drone was from me was turning erractically.  I finally got the drone back but wondered if anyone has had a similar problem. I've seen other treads which indicate the same error message but so far the other messages related to the screen/monitor but in my case, the drone did not respond to the controller.

I found 1 possible for you. Turn OFF wifi, bluetooth and mobile data. This did it for another user. post #17
https://forum.dji.com/thread-229457-1-1.html  

Hello there. I am sorry for the trouble and thank you for reaching out. Can you please try to uninstall and reinstall the DJI Fly application on the said mobile device and can you please try to check if you could limit the capacity of video cache that would save in the application and enable the automatically delete the old cache. Thank you.