It's not that when she open the GMB, a BMB comes out but it was when she unwrap the gift, it reveals BMB instead of GMB. I wasted 2 GMB, ie 1000 coins as a result!
I got a very horrible experience today. I tried to sent a GMB to a friend, and turned out she received a BMB!!! I did it for the second time, she still received a BMB... AWFUL.... Is a total cheat!! What's happening?!