Why does the screen not go out occasionally when making a voice call with the REDMI A3?

When making a voice call, the screen on the REDMI A3 can not be turned off occasionally when the phone is attached to your ear because the proximity sensor, which is located in the upper third of the touchscreen panel (TP), can not properly detect proximity. This sensor is only effective in this specific area during calls. To ensure the screen turns off as expected, try to keep the phone's upper third as close to your face as possible to reduce any physical distance from the sensor.