It's odd with face unlock sometimes I will try to use it and it won't work, and lightning has some affect it too. I notice being in a room with low lightning I have trouble a few times. I was out in the sun and it opened quick. I think maybe the one U.I. 2.0 software on the A71 is like that. I'm hoping the one U.I. 2.1 helps out a little with it when we get the update.