moving events across calendars causes data loss
When moving an event from one calendar to the other via the edit dialog, the original event is deleted and no new event is created.
This is because of https://gitlab.gnome.org/GNOME/evolution-data-server/-/blob/master/src/calendar/libecal/e-cal-component.c#L378 .
This causes this call to fail, but it that failure does not set its error argument. The source event is then deleted here: https://gitlab.gnome.org/GNOME/gnome-calendar/-/blob/master/src/core/gcal-manager.c#L1126 .