Do you have anything other than the default widgets installed? It's possible that something is delaying its rendering of the time.
Also worth noting that most clock faces will actually just update the screen once every second after the screen has powered on. The actual time shown on the screen won't change exactly on the second, it'll change exactly 1,2,3,4,5 seconds after the screen was powered on, so could be as much as 1 second off. Could that be what you're seeing?
Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
But on average it's not actually drifting off?
Do you have anything other than the default widgets installed? It's possible that something is delaying its rendering of the time.
Also worth noting that most clock faces will actually just update the screen once every second after the screen has powered on. The actual time shown on the screen won't change exactly on the second, it'll change exactly 1,2,3,4,5 seconds after the screen was powered on, so could be as much as 1 second off. Could that be what you're seeing?