the latest code for the clock will check the GPS-UTC offset (that is, the leap second count) once an hour at the bottom of the hour. If the default value is wrong, it will set the default to the current value.
One side effect of this command, it turns out, is that the GPS receiver throws away the fix and survey and starts over. This means that the clock will show "no GPS" until a fix is reestablished.
This isn't a huge deal - this will only ever happen once the very first time the clock is powered up past the half hour and once for every leap second after that.
I've sent in an inquiry to SkyTraq to make sure this is an intentional behavior. I'll edit this log when I hear back from them.
I heard back from SkyTraq. The reboot in response to that command is by design.