@shiva-rv Try heating up the IMU by stressing the CPU then shooting it with air to create a large thermal gradient between the silicon of the VOXL2 and the IMU die itself, I predict you'll see the Z bias jump like crazy, but X and Y not so much.
You might also observe that the temperature gradient determines the bias, not the absolute temperature, hence using a temperature model for compensation is useless, and not applied by modal: https://gitlab.com/voxl-public/voxl-sdk/services/qrb5165-imu-server/-/blob/master/server/src/imu_interface.cpp?ref_type=heads#L168
If you're curious about the physics of why MEMs IMUs like ICM42688 act this way I'm sure your favorite AI chatbot could give you a nice explanation about the materials sciences at play here.
Practically, thermally isolate the IMU component as much as possible.