All phones are running all the time, even when turned off. Some do a better job of conserving battery than others. It also depends on what you consider off, some consider it off by just turning off the screen, that's not off. It will use power that way. A full power down shuts most things off, but some things continue to run, as in the power button these days no longer adds / cuts power, it just goes to a chip that wakes up the system. Generally it is just in very low power mode, and sometimes that doesn't work all that well.