So my Phantom 2 with gopro and zenmuse has developed a very strange flight characteristic. It hovers in place just fine, locks onto the GPS in no time, and the compass calibration always works well. BUT, when I am flying in GPS mode and fly forward (or backwards) for a while, when I release the stick it begins to veer off and does a very large toilet bowl, sometimes 20+ feet in diameter. If I correct the toilet bowl with the sticks and stabilize it, it will hover again just fine. It doesn't do this in ATTI mode. So it makes it very difficult to fly in tight spaces because when I fly forward and then release, I have to immediately correct it because it wants to veer and do a toilet bowl forever (it never actually corrects the toilet bowl on its own). Things I have done: - compass calibration many many times - advanced calibration with IMU Thoughts? What is causing this? What can I do to correct it? Again, it is just fine in Atti mode, so there is something going on with the GPS/compass, but only after I have been flying forward or backwards.