I'd clean and test the keyboard/controller/mouse (whichever it is) outside the game and if it is fully working then rebind the heavy attack key in the game. If that works ok then rebind it back and see if that has cleared it. That's assuming logging out of the game and back in again didn't clear it.
I'd clean and test the keyboard/controller/mouse (whichever it is) outside the game and if it is fully working then rebind the heavy attack key in the game. If that works ok then rebind it back and see if that has cleared it. That's assuming logging out of the game and back in again didn't clear it.