Umm, I've been searching everywhere about this problem and have found no information at all. Maybe it's just me, but I lock my phone a lot since I keep it in the front pocket, and since I upgraded to the new OS (4.7.0.148), once out of every four times, when unlocking my phone after it's been locked, the screen is either partially or completely unresponsive for two minutes or more. I was so excited for the upgrade and then this incredibly silly problem arose. What the hell?!