When in direct sunlight, a vampire is to behave as if they have the “Weakened” Status. This means that while we do NOT expect them to make it visible above their heads, they can only pvp-flee / pvp-surrender / pvp-observe.
Vampires CANNOT fight in a pvp during the day.
During the day you can still fight in caves / the Underdark where the sun doesn’t reach
For the sake of timing and duration, the time is locked when pvp-intent is dropped. (Just because your nighttime fight goes until morning does not mean you have to immediately flee)