First let me say that my settings are set to hear me even in the lock screen. But here's the weird thing. It will not react to my voice, then I'll unlock the phone, try it, and it works. Then I'll lock the phone, and it'll work for a while. A few minutes later, it won't respond till I unlock it again. I've retrained my voice plenty of times. And remember, the phone is set to detect my voice even on the lock screen. Any ideas?