I have both digital and analog “atomic” clocks. The analog one does what you described twice annually plus any other is time its off. A dead battery is usually cause for the other times.
It continually goes around and around, both hands without stop for about 15 minutes? Btw, this is a wall clock.
It doesn’t do this twice a year though, as I said it never did this again.
At the time we did replace the battery. While the battery was out the clock was doing nothing. When we replaced the battery it went right back to doing it.