If you select the AutoUpdate option from the Time and Date settings it should keep time with the carrier's date/time sync. If that's active, try deactivating it. Does it improve? If so, your carrier might have issues with their date/time stamp.
Thank you! I found Automatic date & time, which was unchecked, under Date & time settings. It immediately reset the clock to the correct time. Thanks again! This is my first smarter than me phone, obviously.