Why does the screen of the Redmi 14C turn on or turn off during calls?

The screen-on/off function during calls is activated by detecting the proximity of the face to the screen. If the ear's contact area during a call is too small or if the distance to the face is too great, it will not be detected, resulting in the screen not turning off. During extended calls on the Redmi 14C, the screen automatically turns off for power saving. If the screen remains off for a long time during a call or if the power button is accidentally touched, the screen won't automatically turn on when your face moves away from the screen. In this case, you can press the power button to turn it on.
This is not a product quality issue. Please feel assured to use the phone normally during calls with proper posture.