I have the same issue with S6 edge. I can manually set the time but if I choose "Automatic Date Time" it changes my time zone to Mountain when I'm actually located in the Central Time zone.When I attempt to clear cache by holding Power+VolumeUP+Home, the screen shows "Installing System Update", The update fails. I checked in settings and the last update was 2-1-17 and it can not find a newer update to install from that screen. My wife's S5 is set to "Automatic Date Time" and it works fine. What to do next?
I have same issue with a LG K20V. And it started after switch to DST. I have two other phone in the house, Pixel and Droid2, which do not have the same ssue off the Verizon signal. I have toggled to manual and back, powered off and no change. Flew to Denver for a week, the network picked up and I stayed appropriately on MDT the entire trip. Turned to Airplane mode, flew to ATL and it worked fine. Flew back home to Panama City, did approprite Airplane off/on for the fight, and went back to CDT for a short time before it rolled back to MST.
I have done all the on/off toggle tricked recommended on many other threads. I have no idea what is causing the override -perhaps an app has a hidden push I don't know about.