IMU (Temp) and heater stepped and noisy data

Hello everyone, I am analyzing the IMU temperature data from my flight controller. As shown in the graph, the heater temperature appears relatively smooth, but the individual IMU temperature readings are more stepped and noisy. Could someone please explain why this difference occurs? Is this due to the temperature sensor resolution, update rate, filtering, logging rate, or the way ArduPilot reads and logs the IMU temperature? I would appreciate any guidance on whether this behavior is expected.

That is expected.