are these bookings active? (By default only on payment, by paid events -> see other tickets - when you disable all payment plugins they will be by default active, like on free events - additionally there is a setting -> New bookings active, for that).
Only active bookings reserve a slot, so when they are pending they are not taking any seat (like in your case).
Number of bookings not shown in overview
5 years 10 months ago #30745