Yaw changes when roll and/or pitch change

[chinmaybhale]

I have noticed that when using the IMU with the madgwick filter, the yaw changes when the IMU is tilted either in its roll or pitch axis even if there is no movement in the yaw axis. This error is significant enough to be 20 degrees or more in some cases. I understand that this error can happen when the values from the IMU are not fed into the filter in the NED space but from what I understand, that has been implemented in the MPU9250.py file already, so what gives? Is this happening with anyone else and what are the possible fixes for this?