Lollipop's Trusted Face can be bypassed by camera I have enabled Trusted face, also it comes with pattern lock if face is not recognized.

But it has a flaw, anyone can unlock the phone with camera/phone call shortcut on lock screen. As shown in attached screenshot, is it possible to prevent this?
I tried what you're saying a few times, and after you close the camera, you're back on the lock screen.

Unless you were actually looking at the phone, it recognized your face and it unlocked itself milliseconds before opening the camera.

You can notice that the "symbol" in the middle goes from that of a person to that of an unlocked lock when it recognizes you