Every now and then but way to often – mainly at the most inconvenient times – my Moto G will not allow me to unlock the screen. I use the pattern lock, but I have the same issue using another type of screen lock.
When I successfully unlock the phone it gives out a klonk-klonk sound. When I am not able to unlock it does it twice klonk-klonk klonk-klonk. As in unlock-lock.
I use Dual SIM and my first SIM card is tied to my personal Google Account, while the second SIM card is from work and is using Email connected to an Exchange Server at work.
The only kind of pattern I see is that when I am able to unlock after a couple of unsuccessful unlocking attempts, there is usually a new email or text waiting.