diff --git a/addons_extensions/whatsapp/models/discuss_channel.py b/addons_extensions/whatsapp/models/discuss_channel.py
index 7fb18c9cf..e2989c112 100644
--- a/addons_extensions/whatsapp/models/discuss_channel.py
+++ b/addons_extensions/whatsapp/models/discuss_channel.py
@@ -201,7 +201,8 @@ class DiscussChannel(models.Model):
                         subtype_xmlid='mail.mt_note',
                     )
             if partners_to_notify == channel.whatsapp_partner_id and wa_account_id.notify_user_ids.partner_id:
-                partners_to_notify |= wa_account_id.notify_user_ids.partner_id
+                partners_to_notify += wa_account_id.notify_user_ids.partner_id
+            partners_to_notify = self.env['res.partner'].browse(list(set(partners_to_notify.ids)))
             channel.channel_member_ids = [Command.clear()] + [Command.create({'partner_id': partner.id}) for partner in partners_to_notify]
             channel._broadcast(partners_to_notify.ids)
         return channel