This afternoon, I had a compass error come up in the middle of flight that dropped me out of POI mode. I had actually compass calibrated just before flight and was testing different speeds around a pond at about 125feet. I was going about 12MPH in a large circle when the error message came up. The bird did not do anything dangerous, thank goodness, and the error message went away when it came out of POI mode. I don't remember the exact wording of the error message but it was something like, "A compass error has occurred. You have been returned to ... mode." I recalibrated and checked values and all was well, went back into the air and all was well. I wonder what happened. Could have been a fluke, but could a faster rate of speed in the circle somehow have overwhelmed the flight controller and processing needed? Could POI flying somehow affect the IMU or compass? I don't know. It was interesting, though, that it dropped out of POI mode and gave me an opportunity to bring her down safely.