Why does the rice become hard or smelly in the keep warm mode of the Xiaomi Multifunctional Rice Cooker 1.5L?

To resolve the issue, please check the following:
1. Confirm whether the keep warm time has exceeded 12 hours;
2. Verify if the bottom of the inner pot is deformed, causing uneven heating;
3. Check for any foreign objects or deformations near the bottom of the inner pot or around the bottom sensor, affecting temperature control accuracy;
4. Confirm if the surface of the aluminum cover of the bottom sensor is deformed.