Default [Q] New Knock On Password Feature Keeps defaulting back to swipe

Like many other I got the ATT update a few days ago with the new Knock On unlock pattern feature. I really like it and began using it right away. The problem that I am having is that it seems to work for maybe half a day or so and then all of a sudden it is not working and it takes just the old regular double tap to wake the phone and then a swimpe (my former default method) to unlock the phone.

It is like the phone is changing the option back to my default. Anyone else experiencing this?