diff --git a/addons/account/models/account_move.py b/addons/account/models/account_move.py
index 7bfff747fdd..13ca6ebd4b5 100644
--- a/addons/account/models/account_move.py
+++ b/addons/account/models/account_move.py
@@ -1795,10 +1795,10 @@ class AccountMove(models.Model):
             return self.env.ref('account.mt_invoice_validated')
         return super(AccountMove, self)._track_subtype(init_values)
 
-    def _get_creation_message(self):
+    def _creation_message(self):
         # OVERRIDE
         if not self.is_invoice(include_receipts=True):
-            return super()._get_creation_message()
+            return super()._creation_message()
         return {
             'out_invoice': _('Invoice Created'),
             'out_refund': _('Credit Note Created'),
diff --git a/addons/crm/data/mail_data.xml b/addons/crm/data/mail_data.xml
index 28253e529b5..d6e6015e2a5 100644
--- a/addons/crm/data/mail_data.xml
+++ b/addons/crm/data/mail_data.xml
@@ -15,7 +15,7 @@
             <field name="hidden" eval="True"/>
             <field name="res_model">crm.lead</field>
             <field name="default" eval="False"/>
-            <field name="description">Opportunity created</field>
+            <field name="description">Lead/Opportunity created</field>
         </record>
         <record id="mt_lead_stage" model="mail.message.subtype">
             <field name="name">Stage Changed</field>
diff --git a/addons/hr/models/models.py b/addons/hr/models/models.py
index dd615798364..fcad66113ba 100644
--- a/addons/hr/models/models.py
+++ b/addons/hr/models/models.py
@@ -16,5 +16,5 @@ class BaseModel(models.AbstractModel):
                 employee = self.env['hr.employee'].search([('user_id.email', 'ilike', email_address)], limit=1)
             if not employee:
                 return _('restricted to employees')
-            return True
+            return False
         return super(BaseModel, self)._alias_get_error_message(message, message_dict, alias)
diff --git a/addons/mail/models/mail_channel.py b/addons/mail/models/mail_channel.py
index 70f0d9eb78c..c4c8b7fbb58 100644
--- a/addons/mail/models/mail_channel.py
+++ b/addons/mail/models/mail_channel.py
@@ -391,7 +391,7 @@ class Channel(models.Model):
             author = self.env['res.partner'].browse(message_dict.get('author_id', False))
             if not author or author not in self.channel_partner_ids:
                 return _('restricted to channel members')
-            return True
+            return False
         return super(Channel, self)._alias_get_error_message(message, message_dict, alias)
 
     def init(self):
diff --git a/addons/mail/models/mail_thread.py b/addons/mail/models/mail_thread.py
index 9899c2a0692..24d85f79f70 100644
--- a/addons/mail/models/mail_thread.py
+++ b/addons/mail/models/mail_thread.py
@@ -284,14 +284,16 @@ class MailThread(models.AbstractModel):
         if not self._context.get('mail_create_nolog'):
             threads_no_subtype = self.env[self._name]
             for thread in threads:
-                body = thread._get_creation_message()
                 subtype = thread._creation_subtype()
                 if subtype:  # if we have a subtype, post message to notify users from _message_auto_subscribe
-                    thread.sudo().message_post(body=body, subtype_id=subtype.id, author_id=self.env.user.partner_id.id)
+                    thread.sudo().message_post(subtype_id=subtype.id, author_id=self.env.user.partner_id.id)
                 else:
                     threads_no_subtype += thread
             if threads_no_subtype:
-                threads_no_subtype._message_log_batch(bodies={t.id: body for t in threads_no_subtype})
+                bodies = dict(
+                    (thread.id, thread._creation_message())
+                    for thread in threads_no_subtype)
+                threads_no_subtype._message_log_batch(bodies=bodies)
 
         # post track template if a tracked field changed
         threads._discard_tracking()
@@ -414,7 +416,7 @@ class MailThread(models.AbstractModel):
         """
         return self.env['mail.message.subtype']
 
-    def _get_creation_message(self):
+    def _creation_message(self):
         """ Get the creation message to log into the chatter at the record's creation.
         :returns: The message's body to log.
         """