Changing recurrence from custom to none has no effect

[tomslominski]

Thanks for a great plugin, first of all. We wanted to develop our own front-end for events functionality anyway, and this plugin covers all the back-end functionality perfectly.

I've noticed that changing the recurrence option of an existing event from custom to none doesn't seem to do anything, however. After saving the post, all of the previously-recurring events still exist and the option is still set to "Custom".

Steps to reproduce:

1. Create a new event with Recurrence set to "custom", with some dates selected in the calendar underneath.
2. Save the event.
3. Check the "This is a recurring event. Check to edit this event and its recurrences", change Recurrence to "none". Leave the calendar alone - in theory, this should stop the event from recurring.
4. Save the event.
5. Notice the Recurrence is still set to "custom" and all the previous recurring events are still shown in the calendar.

This is on WordPress 6.6.2 and Event Organiser 3.12.8.