E-compass inaccuracy: 90° turn reads as 60° - fix?

Why the e-compass is not accurate, for example, when the sensor rotates 90 degrees, the code only shows that it has rotated 60 degrees?
2024-07-11 21:45:23 The electronic compass is calculated by the geomagnetic data fed back from BMM350, not the original data directly from BMM350. So the compass angle is easy to receive external electromagnetic field interference and inaccurate, if you want to minimise the error of the compass angle, it is recommended to test in an environment without electronic devices.
Tonny12138
