When you press the home button, the phone responds as if you pressed it twice. If you are in the stock launcher, slide to one of the other home screens besides the default home screen, and then launch an app, when you press home, it should bring you back to the last home screen you were looking at. A second press of home, while in the launcher, should bring you back to the default, center home screen. What happens with the Maxx with the 4.4 update is that the phone sees the press of home and brings you back to the launcher, then immediately back to the default home screen. When you are in an alternate launcher that defines a specific action for a home double tap, it does that specific action. The Maxx did not do this prior to the 4.4 update - this is clearly a bug.