I've been using my Spark/controller for about 6 months now, without any major connection issues. But this past weekend, I was flying and the app crashed 3 times during one flight. I was able to restart the app, and it picked up where it left off, but it's obviously disconcerting. No problems with the previous flight, nor with the following flight. I have a Motorola Z2 Play (android). Strange behavior indeed.