Ok.. just took the H Pro out for the first time. Everything was fine for the first 5-10 mins, then I saw it start drifting in a circle. I'm linking a video here. Control became extremely erratic - thankfully I know how to fly one of these things and got it back to me and landed it. Once it was on the ground the ST16 started vibrating and it said "NO GPS" The controller said it had 16 sats, but also said it wasn't locked in to GPS. I shut the H down, and restarted.... Swapped to a new battery after landing - kept her super close for the rest of the test flights and everything seemed fine. Any idea what may have caused this? I did a compass calibration before the first flight.