diff --git a/addons/calendar/models/mail_activity.py b/addons/calendar/models/mail_activity.py
index da30c6629d4..b8a71d4a29b 100644
--- a/addons/calendar/models/mail_activity.py
+++ b/addons/calendar/models/mail_activity.py
@@ -28,15 +28,21 @@ class MailActivity(models.Model):
         return action
 
     def _action_done(self, feedback=False, attachment_ids=False):
+        events = self.calendar_event_id
+        # To avoid the feedback to be included in the activity note (due to the synchronization in event.write
+        # that updates the related activity note each time the event description is updated),
+        # when the activity is written as a note in the chatter in _action_done (leading to duplicate feedback),
+        # we call super before updating the description. As self is deleted in super, we load the related events before.
+        messages, activities = super(MailActivity, self)._action_done(feedback=feedback, attachment_ids=attachment_ids)
         if feedback:
-            for event in self.calendar_event_id:
+            for event in events:
                 description = event.description
                 description = '%s<br />%s' % (
                     description if not tools.is_html_empty(description) else '',
                     _('Feedback: %(feedback)s', feedback=tools.plaintext2html(feedback)) if feedback else '',
                 )
                 event.write({'description': description})
-        return super(MailActivity, self)._action_done(feedback=feedback, attachment_ids=attachment_ids)
+        return messages, activities
 
     def unlink_w_meeting(self):
         events = self.mapped('calendar_event_id')