This is happening to me too. I did get a gimbal overload message and since that day, this keeps happening. My AC keeps disconnecting. The only way it works is is I keep the camera pointed down at the ground...then I don't get the compass error. I guess it's going to make a trip to DJI for repair. darn.
The compass may need degaussing, find someone who repairs analogue tape equipment or CRT displays, they should have a degaussing wand. Had the AC been close to strong magnetic fields?
Not that i know of , did calibrate a couple of weeks ago thinking i was in a open green area , had trouble calibrating then when i walked through the trees to find a better spot there was a mobile phone mast with about 50 antenna on it being disguised by the trees but would that affect it
Have flown since and checked all the compass values and flys good holds position with gps had no problems that way , but had to shut the drone off went to turn back on 10 min later after it had been flying ok then got another compass stuck error