@Zoe31
No, this is unusual Zoe. Payments are automatically generated, they are not subject to manual intervention. If you have received payments in the past you know the system is working correctly.
How close to the hosting did the booking request come? Was it within a week?
Sometimes (particularly where Instant Book is involved) events get ahead of the systems ability to keep up. There may have been a problem with the guests verification. Did you receive any notification from ABB suggesting that the reservation was subject to payment confirmation?
If there were no issues with the booking and your received reservation confirmation prior to the guest arriving, get onto Airbnb on 02 8520 3333. You will find them quick and effective! If it puts your mind at rest, in 37 ABB hostings I have never had a payment that did not arrive on time and for the correct amount. It is generally very reliable!
Good luck with it Zoe
Cheers......Rob