I have exactly the same problem with my 2005 Cessna 206! They replaced the magnetometer but no help. Cessna offered no help. Garmin says it is a software update compatibility problem. The local avionics shop who actually arranged a refund on the magnetometer said to wait for a “hard failure”. This has been going on for 3 years and is still going on. It only occurs about every 20-40 hrs of flying. I even considered replacing the G1000 but even Garmin said that it would not solve the problem. I’ve learned to live with it. The only problem is that it disengages the autopilot and should this happen in IMC on an approach I need to be prepared. Hope you are having better luck!
