It shouldn't buffer them like the author describes. It should execute the button’s function immediately when pressed. This might mean to cancel the current animation and jump ahead, or it might mean to speed it up by the appropriate factor so it takes the same amount of time as it does for one button press. Either way is massively preferable to a button that swallows my input.

One way to deal with it could be “guaranteed interrupt” action (something like sigkill, just for UI action queue).

Other way could be to actually visually indicate action queue depth.