I'd say it's the opposite. It's the sequel to one of the lowest grossing MCU movies, and it's doing the numbers you'd expect, yet 'flop' is being thrown around. This movie doesn't do anything too different from the first one, and his appearance in Civil War was overshadowed by Spider-Man and Black Panther. I understand if the movie was significantly better than the first one, like in Winter Solider's case, but it's really not. They are more or less on par. Yet it's still increasing just by a virtue of being an MCU sequel.