Apparently it sporadically happens to various lucky users after all firmware updates including the latest to 4.3!! Though the link references problems after a 2013 update, it explains why the wrong setting "Global Network" sucks the life out of your battery and your signal switches from 3G to 4G or none at all! https://subnet.ischool.syr.edu/2013/...date-to-4-1-1/
Apparently, my settings had never been altered until this last update, almost 2 months later and I've had 4G constantly since I changed my settings!
Verizon & other carriers, I think you need to train your folks on this SIMPLE EASY to FIX issue instead of ???????!!!!!!!!!!!!