What we have been seeing is that the two sensors in the tank that measure the actual level of the fuel in the bladder have become out of adjustment and need to be reprogrammed to set the proper fuel level. chances are that the tank is actually full and is just reading emtpy or low. once the sensors are reset. you might not have the problem you are describing anymore.

you might also have a restriction in the vent system that lets the air around the bladder escape through the charcoal cannister to the engine to be burnt.
we have not seen alot of these cases but I'm sure it is possible that this could happen.