diff --git a/client/modules/crm/src/views/calendar/calendar.js b/client/modules/crm/src/views/calendar/calendar.js
index e8a110044e..17cf166b4b 100644
--- a/client/modules/crm/src/views/calendar/calendar.js
+++ b/client/modules/crm/src/views/calendar/calendar.js
@@ -1197,7 +1197,8 @@ class CalendarView extends View {
 
         const event = this.convertToFcEvent(attributes);
 
-        this.calendar.addEvent(event);
+        // true passed to prevent duplicates after re-fetch.
+        this.calendar.addEvent(event, true);
     }
 
     updateModel(model) {