I am currently running the latest nightly CM11 on my AT&T LG G2 and have been experiencing this issue for about 2 months now. Several times each day, when I go to unlock my phone it will be frozen. i can see the screen but cannot touch anything on it. This issue I thought may have been a glitch with the lock screen I was using (stock slide to unlock) so I disabled it and still have this issue. I have spent about an hour researching the issue but have not found anyone else complaining of this (or I am using the wrong search terms). Thanks in advance everyone!