During gameplay, after sleep, the watch of the host may show a different time or day to the watch of Player2. This does not occur every time the players sleep, but may occur during a gameplay session.
@SmokedLargeMeat has reported that they have managed to avoid the watch desync by having Player2 initiate sleeping in their save. [PS4][Bugs] Date on watch not the same for both players
Players who do desync have reported reloading can resync the watches. It may also be possible to resync by sleeping again, however it is unknown if the desync will affect anything else while it exists.
As this does not happen every time the host sleeps, if you notice this occurring in your save, please let me know if you can recall everything done by the host before sleeping caused a desync as there may be something else triggering the issue.