Lost registrants to all sessions > Meeting set up as recurring sessions with registration

We recently set up a series of events (as Zoom Meetings). They were set up as recurring events with the ability to register for each session through a checkbox. We periodically checked to see how many had registered for each event and saw that the sessions had about 40 registrants each. About a week ago, we added another session to the occurrences.  After we did that, we noticed that ALL registrants to all sessions had disappeared - all sessions were reset to zero. Any help you can provide will be appreciated!