Hello @Boris02608!
Something else to keep in mind about buffers is that if they were turned on when these bookings were made, they will still apply and block out those time slots, even if you’ve since turned them “off” in your event type settings. All settings that are in place when an event is booked are “locked in” for those bookings.
What you’d need to do in order to remove those buffer times from bookings made when they were in place is cancel and reschedule the bookings. This will effectively put the new settings in place - sans buffers!
You can read more about buffers and how they work here in our Help Center!
If the buffers were not turned on when these bookings were made, I would resort to your connected calendar to see if there are any meetings during those times. If you have buffers turned on for another event type with bookings made, they might be attaching to an issue with duration due to events on your calendar. Let us know if this doesn’t help!