Just another video of someone who hates something none of us have seen yet, and says it breaks canon with no proof to back them up.
You are free to think whatever you want, but it doesn’t change the fact that no one here can give a single point of definitive proof in the film that anyone was talking about the Mustafar duel.
Again, look at the dialogue on its own, not the decades of watching the film and thinking they are talking about Mustafar. Use logic, not your feelings.