Slitherine

I've just returned to Afghanistan '11 after a long delay so this is the first time I'm playing on the 1.1.8 update. I've played through a few times but the game isn't recording the supply trucks that get through to the besieged FOB, therefore I'm automatically losing the scenario despite having sent loadddddddssss of supply trucks through to the FOB by the end of the game. Any ideas? Thanks.