diff --git a/addons/mail/models/mail_thread.py b/addons/mail/models/mail_thread.py
index c9058f9db63..6b4ffcd2ecc 100644
--- a/addons/mail/models/mail_thread.py
+++ b/addons/mail/models/mail_thread.py
@@ -2212,7 +2212,14 @@ class MailThread(models.AbstractModel):
         }
         base_mail_values = self._notify_by_email_add_values(base_mail_values)
 
-        Mail = self.env['mail.mail'].sudo()
+        # Clean the context to get rid of residual default_* keys that could cause issues during
+        # the mail.mail creation.
+        # Example: 'default_state' would refer to the default state of a previously created record
+        # from another model that in turns triggers an assignation notification that ends up here.
+        # This will lead to a traceback when trying to create a mail.mail with this state value that
+        # doesn't exist.
+        SafeMail = self.env['mail.mail'].sudo().with_context(clean_context(self._context))
+        SafeNotification = self.env['mail.notification'].sudo().with_context(clean_context(self._context))
         emails = self.env['mail.mail'].sudo()
 
         # loop on groups (customer, portal, user,  ... + model specific like group_sale_salesman)
@@ -2245,7 +2252,7 @@ class MailThread(models.AbstractModel):
                 if email_to:
                     create_values['email_to'] = email_to
                 create_values.update(base_mail_values)  # mail_message_id, mail_server_id, auto_delete, references, headers
-                email = Mail.create(create_values)
+                email = SafeMail.create(create_values)
 
                 if email and recipient_ids:
                     tocreate_recipient_ids = list(recipient_ids)
@@ -2272,7 +2279,7 @@ class MailThread(models.AbstractModel):
                 emails |= email
 
         if notif_create_values:
-            self.env['mail.notification'].sudo().create(notif_create_values)
+            SafeNotification.create(notif_create_values)
 
         # NOTE:
         #   1. for more than 50 followers, use the queue system
diff --git a/addons/test_mail/tests/test_mail_followers.py b/addons/test_mail/tests/test_mail_followers.py
index fe8c5f38d96..ba2ef2074c8 100644
--- a/addons/test_mail/tests/test_mail_followers.py
+++ b/addons/test_mail/tests/test_mail_followers.py
@@ -270,6 +270,51 @@ class AdvancedFollowersTest(TestMailCommon):
             all_defaults)
 
 
+class AdvancedResponsibleNotifiedTest(TestMailCommon):
+    def setUp(self):
+        super(AdvancedResponsibleNotifiedTest, self).setUp()
+
+        # patch registry to simulate a ready environment so that _message_auto_subscribe_notify
+        # will be executed with the associated notification
+        old = self.env.registry.ready
+        self.env.registry.ready = True
+        self.addCleanup(setattr, self.env.registry, 'ready', old)
+
+    def test_auto_subscribe_notify_email(self):
+        """ Responsible is notified when assigned """
+        partner = self.env['res.partner'].create({"name": "demo1", "email": "demo1@test.com"})
+        notified_user = self.env['res.users'].create({
+            'login': 'demo1',
+            'partner_id': partner.id,
+            'notification_type': 'email',
+        })
+
+        # TODO master: add a 'state' selection field on 'mail.test.track' with a 'done' value to have a complete test
+        # check that 'default_state' context does not collide with mail.mail default values
+        sub = self.env['mail.test.track'].with_user(self.user_employee).with_context({
+            'default_state': 'done',
+            'mail_notify_force_send': False
+        }).create({
+            'name': 'Test',
+            'user_id': notified_user.id,
+        })
+
+        self.assertEqual(sub.message_partner_ids, (self.user_employee.partner_id | notified_user.partner_id))
+        # fetch created "You have been assigned to 'Test'" mail.message
+        mail_message = self.env['mail.message'].search([
+            ('model', '=', 'mail.test.track'),
+            ('res_id', '=', sub.id),
+            ('partner_ids', 'in', partner.id),
+        ])
+        self.assertEqual(1, len(mail_message))
+
+        # verify that a mail.mail is attached to it with the correct state ('outgoing')
+        mail_notification = mail_message.notification_ids
+        self.assertEqual(1, len(mail_notification))
+        self.assertTrue(bool(mail_notification.mail_id))
+        self.assertEqual('outgoing', mail_notification.mail_id.state)
+
+
 @tagged('post_install', '-at_install')
 class DuplicateNotificationTest(TestMailCommon):
     def test_no_duplicate_notification(self):