Why doesn't the Xiaomi 15T Pro screen turn off during calls?

Thank you for your support of Xiaomi. On the Xiaomi 15T Pro, the screen remains on during a call if the proximity sensor is obstructed. The sensor detects when the phone is held close to the ear. Obstruction by hair, accessories, or other objects can prevent it from functioning correctly.
When the proximity sensor is blocked, the device cannot recognize its position relative to your ear, causing the screen to stay on instead of turning off automatically. This is normal and indicates the sensor's protective function, not a device malfunction.
To ensure proper operation, make sure the proximity sensor area is clear of any obstacles. Keeping the sensor surface clean ensures accurate detection, allows the screen to turn off correctly during calls, prevents accidental touches, and maintains a smooth calling experience.