I'm not sure what your question is -- was the reservation request from a different person? If so yes that is how it works. When you preapprove someone, if they don't go ahead and book, someone else can jump in with a reservation request for the same or overlapping dates and block the first party from booking. Reservation requests block the dates, preapprovals don't. Which is why guests serious about booking should book right away rather than sitting on a preapproval. It's good to tell guests when you preapprove them that the preapproval does not hold the dates for them. Some think it does, and they delay, and then they may find out the meaning of "you snooze you lose" when they lose the opportunity because someone else jumped in and booked.
If guest tries to book thru a preapproval and it wont' go thru, or changes to not possible, then the guest will definitely get info from Airbnb on why they weren't able to book -- usually it is a payment problem or an issue about verification that they need to complete.
