Hello everyone! We have enabled the "Allow registrants to create their own agenda" feature at our event. Accordingly, interested parties can choose between three different sessions in the event portal and register for them. However, for one of our registrants we only get the event registration displayed in the backend, the session registration remains empty. No cancellation has taken place. In the marketing form submission of the associated custom form, it says "undefined" under "d365mktEvent_attendeeSessions" instead of the ID of the corresponding session(s). So we also have no information about which session he is interested in and cannot manually add it.
We would be very grateful if someone has a short term solution or idea how to proceed in this case.