As the title says, I’ve tried to complete the “mastery loader” objective on Tees Valley Line, however when I completed a service where you load coal into the wagons in timetable mode (6E07 Scunthorpe - Redcar and then once in free roam I did 0Z07 Redcar Ore Terminal), I checked back on the progress and it said no progress had been made? so what I am asking is; is this a bug or do I need to complete the “coal hauler” scenario 3 times just to complete the objective? If it is the latter, then that is an absurd amount of time for one objective because it’ll take you roughly 3 hours of repeating the exact same scenario.
best way to get Mastery to update is to exit to the Main Menu on the game after completing a scenario, then exit the game and restart it.
Exit to the main menu after completing the service should be enough. From what I've noticed, this updates the mastery. Failing a service after SPAD also updates the mastery (discovered this Monday). On the other hand, exiting to desktop usually doesn't progress the mastery even when completing the service and also exiting in the middle of a service doesn't.