The phone is always unlocked once anyone press the power button, it shows the unlocked lock sign always, although I added pattern, fingerprint, face recognition but just don't lock.
Please review your phone's Smart Lock settings.
Settings > Lock screen > Smart lock
I have the same problem but resolved it. I figured that I had to disable face recognition and enable fingerprint. It works with pattern, pin and password. Just don't enable fingerprint and face recognition at the same time.