You may also want to change the Direction on your Keyboard watcher to "Up" to prevent multiple triggers (since holding down the spacebar too long with the Keyboard Watcher set to "Down" can trigger the Keyboard watcher in the Scene your transitioning from AND the Scene you're transitioning into).
Adding a Multiblocker actor between the Keyboard Watcher and the Jump Actor is another way to prevent accidental activation of more than one Jump actor.