Why does the screen of the POCO M6 Pro not turn off when receiving a call?

The issue is due to limitations in the ultrasonic algorithm used for proximity sensing. This can cause the screen to remain on briefly when the phone is quickly placed against the ear during an incoming call. However, the screen will turn off once the call is answered and the earpiece is functioning properly. This behavior is related to how the ultrasonic sensor processes proximity changes and resolves itself once the call is established and the sensor recalibrates.