Even if you have your BD*G FF number posted on your UA boarding pass it doesn't mean that the flight will actually post to BD. Couple of my flights posted to United instead and this was after I had made sure that both of the FF numbers were correctly put to the itinerary. One for the status benefits purposes and one for posting.

The only way to ensure that the miles will go BD is to ask the agent to entirely erase your UA MP number form the itinerary. It shouldn't be like this but this is UA after all.