Are you getting wonky readings from the magnetometer on your IMU? Do the compass headings make no sense at all? Your magnetometer may have become magnetized to the point that all the readings are distorted by its own magnetic field. This can happen if your magnetometer is exposed to a strong magnetic field, like getting too close to a magnet or an electric motor.
The good news is that you can fix this with an inexpensive magnetizer/demagnetizer tool available for just a few dollars at your local hardware store or home improvement center. Just wave the sensor back and forth over the stepped part of the “demagnetize” side of the tool to neutralize the magnetic field.
Read more about this in this forum post