Sometimes you can get them re-adjusted/calibrated and they’ll work fine again, sometimes you are better off getting a new compass. I had one that was adjusted and worked good for another couple years, but I ended up replacing the compass later on, I had a early model autopilot (first year they switch to an all black color scheme) and Minnkota had a newer version of the compass and I put that in it worked better than before, and no more issues, I don’t own that boat anymore, but I haven’t heard of any more problems (not saying there hasn’t been) Autopilots can be a bit fickle, and seem to want some “attention” every once in awhile, but IMHO it’s all worth it when they are working right
BTW I changed out the compass myself, not rocket science there, pretty much pop the cap off, unplug a couple wires, and plug in the new one. Otherwise any Minnkota service center should be able to take care of you
BTW I would say this is a common issue, wither that makes you feel better or not, I’m onto my second auto pilot (terrova) and I’ll buy another when the day comes.