When saving a game (at least on land), the time shown for the in-game time before you save (when hovering on the "new save" selection) seems correct, but the time shown for already saved games is wrong and seems to be improperly using the real life time mixed with the game date.
For example, I just went to save, and it reported on the "new save" that the time in game would be January 1, 1721 13:59. When I then complete the save, and then reopen to save menu, the saved game says the time is January 1, 1721 17:34. 17:34 is the correct time real world time where I was, but the date is obviously not January 1. January 1 13:59 seems like the correct in game time, but it doesn't actually get recorded as that when you actually save.
For example, I just went to save, and it reported on the "new save" that the time in game would be January 1, 1721 13:59. When I then complete the save, and then reopen to save menu, the saved game says the time is January 1, 1721 17:34. 17:34 is the correct time real world time where I was, but the date is obviously not January 1. January 1 13:59 seems like the correct in game time, but it doesn't actually get recorded as that when you actually save.