When the BFG has breakfast at Buckingham Palace, he drinks from a cup before complaining that there isn't any frobscottle in it. But after Sophie shushes him, the cup disappears from view and is never seen again.
When the BFG opens the window to the Queen's bedroom, the Queen is asleep facing the window. But after Sophie has stepped into the bedroom, and the BFG has blown the dream through his trumpet, the Queen is lying facing the opposite direction.
During the musical number 'Sometimes Secretly' in dream country, there is a brief moment where Sophie is drawn twice (just as the words 'and you tumble and glide' are sung).
BFG states that humans are the only animal to kill each other. In fact, there are a vast number of animals which kill other animals of the same species. Cats, which the BFG specifically mentions, are well known for killing members of their own species (BFG has said that he has little education.)