Event Time Changing

I'm not sure if this is the right place to post this. One of our events' time changed from Noon CST to 1 PM CST. We know it changed because one of our employees previously registered for the event and it comes up on her calendar at the correct time, Noon CST. However, I just registered for our event today and my confirmation email as well as the calendar event had the event start at 1pm CST. Was there a recent update or something that could have done this?