The miles for my first and only stay booked through DeltaAirbnb.com took 10 months to post. I sent in a request via the Delta website about two months after my stay. After six months, Delta sent an apology via e-mail, and added some SkyMiles to my account (actually more miles than I ended up receiving for the booking itself).

My wife had a stay in January that hasn't posted yet. Again I sent in a request two months after the stay. Delta sent a random e-mail a few weeks ago saying they are still working with Airbnb to get the miles credited. She did not receive any customer service miles, but she has no Delta status.