Apple Watch keeps slipping an hour ahead.

My wife and I both have Apple Watch series 3.l with cellular. For the last couple of months, both watches randomly skip ahead an hour. Eventually, it will move back to the correct time on its own.

both watches are paired to our iPhones. The phones always show the correct time.

This affects both watches - sometimes hers, sometimes mine. Seems to happen at completely random times.

We are in Atlantic Canada, so on Atlantic time zone. Our carrier is Bell. Not sure if any of that matters.

anyone have ideas how to correct this?