Can't Forget Moves for New Moves

[Tominatorftw]

When I was playing this game one day, my Gyarados and Heracross got to a certain level to learn a new move. I liked the moves that the game offered my pokemon to learn and pressed the move I wanted to forget and then confirmed that wanted to forget that move. But when I checked my moves for both and battled with both, their moves didn't change, they both still had the same moves. I restarted the game, but still had the same moves for both. So please help me by fixing this bug because this is a really good game.