Even though the availability is synced between Sirvoy and the channels almost instantaneously, there is always a small risk of double bookings when the same physical room is made available on multiple booking channels simultaneously. For example, the last room could in the same instant be booked both through your website and another booking channel.
Overbookings can also occur due to incorrect room type mappings. For example, if the booked room type has not been mapped, Sirvoy will not be able to add the booking correctly and it will be flagged as an overbooking.
When an overbooking occurs, the booking channel will expect you to inform them and perhaps also work out another solution, depending on your agreement. The best way to avoid overbookings is to limit the number of rooms shared with booking channels.