Hey there. That's a technical issue. Sometimes it helps to cancel your subscription and click it again. Worked for me in various communities. There's no mod approval or something for subscriptions.
The forward propellers help achieve a higher speed. The main rotor can spin slower while the propellers give the aircraft more forward speed so that more lift is created by the rotor disc and stubs. The rotor has to spin slower to avoid it's tips going transonic. This thing can travel at 407 km/h cruise.