Issue No. 2: iPads don’t handle heat very well. I quit using my iPad Pro during 90+F wx because it would overheat and shut down, just like yours did.
I'm having the same exact problem as the original poster did. I suspected that the firmware screwed everything up because I hadn't used the drone for over a year. Before I updated the software everything was working fine. Before the next time out I accepted the update and after that I had problems exactly as the OP did. So I will heed his advice and do exactly as he did. Wipe everything out and start over. Fingers crossed!