this is a very unusual setup. Most people use one FSM to get buttons etc, and then send events to other FSMs accordingly. But yours should be possible too.
Like, you could put the actions from the jump state into your main state. Then replace the GetButtonDown action with a GetButton action.
That action will make the bool True if the button is pressed, and false if it isn't. So if you use it to set the Bool you use in the SetProperty action for jump, and make both of them work every frame, it should work, shouldn't it?