The altimeter isn’t the problem I don’t think. I set the correct altimeter with B before takeoff and I’m supposed to hold 8000, but my Cessna 172 keeps climbing up to 10K+. Perhaps the Navigraph Navdata did something, but I removed it so it should be back to normal now. A friend who also uses the AI on some parts of the flight doesn’t have this problem and I’d hate to do a sim reinstall just for this.