Possible bug in Bookings with maximum attendee events
It seems if you create a service with multiple attendees and have your staff set to have "Events on Office calendar effect availability" the first person to book the event will create an appointment in the staffs Office calendar and subsequently remove that time slot from being available. It does seem there is a work around if you create a dummy staff member with no Office calendar attached and assign it to the event so it's not a major issue.
