Just experienced this today. I've only had the Inspire about a week, but have been flying without issue. Today I took it over to a mates to give him a demo. It was a nice open area so I decided to fly in ATTI mode for a change. All was absolutely fine. After a while I decided to switch back to GPS mode, and then things started to go funny. The Inspire started performing some really funky movements and wouldn't hold position in a hover at all. I managed to land it (like an idiot I forgot to simply switch back to ATTI mode), but it was hairy for a bit. My IMU is calibrated and I calibrate my compass in each new location. When I turned the Inspire off and then powered it back on again it all worked perfectly in GPS mode. I haven't had a chance to test more, and will do when the batteries are charged. However, has anyone else come across this? Is there a possible bug that occurs switching from ATTI mode to GPS mid flight?