Knock code and fingerprint scanner of LG 5 not working at times?

[AC Question]

I just ordered LG g5 and got it yesterday. However, sometimes, especially when I turn on the phone, the fingerprint and the knockcode don't respond. The way to solve this is to wait for a bit and press the button on the back to relock the screen to return to the always on display. Sometimes, when I have apps opened I encounter the same problem. Is my LG g5 somewhat broken or is this normal?

 

[Kevin Hill2]

Not normal, I would return it for a new one, mine works flawlessly, and has from day one

 

[Jon_Snow9x]

Could it be because of the screen protector which I still have on the screen? I don't know why this happens sometimes but just now, I tried to shutdown and turn the phone on again. No problems encountered this time with the knockcode or fingerprint..