sounds like your internal meters(or shutter speeds on the gear train/transmission in the camera) are a bit slow. I'd be hesitant to call foul on the part of Fuji. More likely your lab(aforementioned "push process" by someone else), or a slightly slow shutter in-camera.

one word:

TEST

Another reason(if you can afford to do it) is to buy in bulk, and freeze until you consume(shoot) it. Not very hard to do, just convince yourself(or if you have a better half, them ) that you "NEED" a film freezer, and they can put the extra frozen veggies in there in case they need some room

-Dan