Is it not lighting the 12 o’clock position at midnight?
Edit:/ If I am understanding you correctly, your watch is set to 0-23 hours and not 1-24. Is that correct? If so, I can add a 12 o’clock indicator set as a zero hour to see it this resolves the bug. It may be something I will need to bear in mind when working with images as “numbers” as it were.