Proximity sensor is oversensitive (was "Screen blanks when making call")

[jsch]

I had a similar issue, caused by the proximity sensor.
Can you please check what

Code:

grep . /sys/bus/iio/devices/iio\:device*/in_proximity_{nearlevel,raw}

provides.
In my case it helped to peel of the screen protector (before raw was always above 25, whereas 15 and above indicate "phone is placed near the ear -- blank screen").