It is NOT fixable (that we could find). That's what we messed with for what seems ~forever~ in FotRSU. The game is bound and determined that the player will get an early Gato (usually not noticeable) and an early Balao, as rewards (we assume) for exemplary performance of your duty - aka: running up the score. We gave up in FotRSU, and when it happens, it happens... Same with the Tench. We can set all the limiting dates we want to, restrict the mission assignments, etc., but in the end, the game decides, and it doesn't care one whit about what the date is. However, if you don't have a mission assignment in for the boat given early, the player either crashes, or they get stuck with the "No Mission Objective Found" error, ad infinitum, ad nauseum...
