there is a solution for this! you need to turn off your phone completely, and when u will be turning it on, press on/off button and volume down one in the same time until u will see honor logo. after that there should open a calibration options - make full test and turn on phone normally. that's all - worked for me.

while incoming call is coming, why should be the display off? why should we press the power button ? is it not a defect in this phone? company does not have a resolution for this ?

Yeah, Sunil is right. It's normally like that if phone display doesn't turn on.

The only option would be t press side power button and check the incoming call screen