OK I see where I was getting mistaken. I was finishing a patrol on say 26 Jan and then appearing in the Admirals Office the next day (27th) but I wasn't paying attention to the date when my next patrol actually left e.g. 2 or 3 weeks after that date from when clicking on the board/map for next patrol.
I think I need sleep
Thanks Armistead for making me go back and check.