Photon OS Change Current Time moved ahead One Hour

I have 2 devices that run continuously. One of them suddenly started activating an hour early. The other was running at the regular time. Checked my web page control and noted that the Current Time which I get from the Photon had moved ahead an hour. The code for both devices is the same. The only difference I could see was that the OS on the correctly running device was 1.5.2. The OS on the ahead device was 2.0.1. I updated the correctly running device to 2.0.1 and it has now jumped ahead an hour. I live in the Central Time Zone (-6) and that is still the setting in the code. I will alter that to fix this problem but any ideas as to why it changed and if it will be changing again?