sync calanders

Im new too booking.com and therefore not sure if i have set something up wrong or not. My issue is when i receive a reservation for 1 night everything seems to be ok , my booking.com calendar is updated and also my air bnb calendar is updated as expected as I have synced them both. However, when i receive a 2 night reservation  from booking.com it appears to only update 1 room in my air bnb calander. As you can imagine a bit of a worry encase i end up double booked...... any help or advice would be great. thanks bernadette