Dealer replaced the intermediate steering shaft on my Macan and invoiced $379 for the repair to Porsche.I just dropped my 2015 S off at the dealer today and notified them of the steering squeaking noise at low speeds.
They told me there is a bulletin out for this. If lubrication doesn't solve the issue, they will need to replace the steering shaft.
Parts included the shaft and several bolts. Keep complaining to your dealer and tell them about the bulletin.