diff --git a/src/panels/calendar/dialog-calendar-event-editor.ts b/src/panels/calendar/dialog-calendar-event-editor.ts
index e76341c474..19965a748e 100644
--- a/src/panels/calendar/dialog-calendar-event-editor.ts
+++ b/src/panels/calendar/dialog-calendar-event-editor.ts
@@ -387,7 +387,7 @@ class DialogCalendarEventEditor extends LitElement {
     const data: CalendarEventMutableParams = {
       summary: this._summary,
       description: this._description,
-      rrule: this._rrule,
+      rrule: this._rrule || undefined,
       dtstart: "",
       dtend: "",
     };