diff --git a/addons/hr_holidays/models/hr_leave.py b/addons/hr_holidays/models/hr_leave.py
index 970c0eb01bf..c5ed9ef6323 100644
--- a/addons/hr_holidays/models/hr_leave.py
+++ b/addons/hr_holidays/models/hr_leave.py
@@ -621,9 +621,7 @@ class HolidaysRequest(models.Model):
 
     def _inverse_supported_attachment_ids(self):
         for holiday in self:
-            holiday.supported_attachment_ids.write({
-                'res_id': holiday.id,
-            })
+            holiday.attachment_ids = holiday.supported_attachment_ids
 
     @api.constrains('date_from', 'date_to', 'employee_id')
     def _check_date(self):