The clocks in my elementary, middle, and high schools would do something similar. Not every minute, but every hour. At the top of the hour, when there was 15 seconds left, the second hand would make 3 second jumps until it hit the top, and then hold until the next hour started.
I always thought that was a brilliant way to keep mechanical clocks in sync. And the system had been there since the 1970s, so it was well before digital clocks were feasible for a school.
I always thought that was a brilliant way to keep mechanical clocks in sync. And the system had been there since the 1970s, so it was well before digital clocks were feasible for a school.