Accelerometer BMI160 changing bias
the problem is asymmetric railing. It only occurs on the Z-axis because it is affected by gravity, when the vibration exceeds the accelerometer's range the asymmetric range causes a bias. When the vehicle is in motion vibration occurs. Solution would be with improved mechanical mounting or artificially clipping the data. See link below:

https://www.analog.com/en/technical-articles/vibration-rectification-in-mems-accelerometers.html