Hi
Dejavu,
Seems something is wrong on the hardware side. Please try running SMMI test to check if this is related to hardware:
How to Enter SMMI_TEST (test hardware)
Go to Calculator=>type " .12345+= "
you will be entered to SMMI_TEST
If there is any hardware related issues please visit the nearest service center. If not, try factory reset on your device. Please report back the findings.