Same Issue

[Ashleyware]

I have no screen protector on my phone, Nor do I have a new one, Is there anyway I can turn this off manually. What a crazy idea to put on a phone though, why would I want my phone locked when i speak on it, I dont press a phone up to my face like a maniac. I cant hang up and it doesnt unlock straight away. Is there anything I can do or is it a case of new phone time. 

[Uliwooly]

If there's anything near the proximity sensor while on a call it will lock the screen so your face doesn't press any key, check if there's anything near or covering the proximity sensor, it could be a protective case.