I have an unstable Loiter condition on my Pixhawk 3.2.1 550 quad, all other modes are very stable and predicable. I am using my Iris+ as a benchmark as both are configured about the same. I am using a CSG M8 GPS and have switched out with a 3DR unit with no change in condition, gps noise and jamin are very similar on the 550 and the Iris but I am not good at reading log files yet so I am hopeful that someone can give me a hand. In loiter the 550 jerks and twitches when doing yaw-roll maneuvers and continues yaw sometimes a full 180 degrees after a fast turn. Drift mode works perfectly and all non-gps modes are unaffected.
Did you find a solution for this ? I am getting these sharp twitches when in loiter, while the copter is trying to hold position.