Major Bug:
On L720, when I finished to play a Youtube's VIdeo, and swip faster to change the video, my screens go freezed, and if I block the phone, my screens goes like when a old TV doesn't has signal (statics). It's very weird, but, the most weird comes when I note that the touch still working, I'm able to go to home, pause the video, open/call randomly, etc.
Is very easy to fix it, just I need to press the power button for 7 seconds and Descend the "Lock Screen", turn it on back and nothing else.