Bookings events deleted on calendar and created as new, deleting old customers

Anyone had an issue where a calendar appointment has been 'deleted' with a fresh one in it's place? Yet those already booked on up until that point got the email notification, still show up as customers in the customer section, but no longer show as being booked onto that session? A new one replaces it allowing new customers to book on.

This has happened to interviews being run. 13 unexpected people turned up, but they all had email confirmations. The current booking information doesn't show them on there, but a previous export does show some of the customers. I have 10 days of missing data, 3 of the later days is where I suspect the error occurred. Went to the mailbox of the staff member and found the email confirmations sent to those people. But now worried about future events. Have 4 interview events each week from now until April and it's like finding a needle in a haystack for anyone else affected by this.

How can an event get deleted without a cancellation email being sent to customers? My calendar admins are adamant they haven't changed any of the service settings of deleted any events or created new ones.