What worries? What issue? And finally, what does it do when holding it up to your ear and pressing the button?
Does it end the call or something? I've honestly never pressed the power button while on a call with the phone up to my face and the screen off. I'd imagine it locks the phone. I know while screen is on and you press the button while on a call, it'll turn off the screen. Press it again and it locks. No?
From what I understand, it used to end the call before (when you were holding it up to your ear) but now it doesn't. Buuut I think I misunderstood you the other day anyway, haha. I was saying that it didn't do anything, but then when I tested it, it ended the call while I was looking at the phone.
So basically, old behaviour: up to ear, it would end call. Now, it doesn't.