"Could it be non-software related issue, such as motor overheating during a long time continuous fly?
When a motor is hot, some non-metal melting parts may cause internal tension increase. It looks like the quad is oscillating with no reason. At some…"

"Hi Seth,
I've tried the app on my 7" tablet connecting directly to Arducopter via a cheap Bluetooth dongle. It works just great in the field as a perfect setup and tuning tool. For flying is more convenient to use MinimumOSD. I'm still figuring out…"