I have never seen this before. In the code, it is related to the compass scale factor. This is a new feature which uses your GPS position to look up what the earth magnetic field strength and scale the compass readings to match the field strength. The error appears when the scale factor is <0.85 or >1.3, because that might indicate that there is interference or there is something wrong with the sensor.
I’m not sure what might be causing the problem, but make sure you do these things:
- have a good GPS lock before starting the calibration
- the sensor is not near metal objects or electronics
- do the calibration in a place that is far away from large metal objects, including reinforced concrete