diff --git a/addons/mail/models/discuss/res_users.py b/addons/mail/models/discuss/res_users.py
index 00befd533e1..7f20ce5d366 100644
--- a/addons/mail/models/discuss/res_users.py
+++ b/addons/mail/models/discuss/res_users.py
@@ -10,11 +10,7 @@ class ResUsers(models.Model):
     @api.model_create_multi
     def create(self, vals_list):
         users = super().create(vals_list)
-        # Auto-subscribe to channels unless skip explicitly requested
-        if not self.env.context.get("discuss_channel_nosubscribe"):
-            self.env["discuss.channel"].search(
-                [("group_ids", "in", users.groups_id.ids)]
-            )._subscribe_users_automatically()
+        self.env["discuss.channel"].search([("group_ids", "in", users.groups_id.ids)])._subscribe_users_automatically()
         return users
 
     def write(self, vals):
diff --git a/addons/mail/models/res_users.py b/addons/mail/models/res_users.py
index 1169ddd9096..559ae1613f7 100644
--- a/addons/mail/models/res_users.py
+++ b/addons/mail/models/res_users.py
@@ -2,7 +2,7 @@
 
 from collections import defaultdict
 
-from odoo import _, api, fields, models, modules, tools
+from odoo import _, api, Command, fields, models, modules, tools
 from odoo.tools import email_normalize
 
 
@@ -53,11 +53,9 @@ class Users(models.Model):
 
     def _inverse_notification_type(self):
         inbox_group = self.env.ref('mail.group_mail_notification_type_inbox')
-        for user in self:
-            if user.notification_type == 'inbox':
-                user.groups_id += inbox_group
-            else:
-                user.groups_id -= inbox_group
+        inbox_users = self.filtered(lambda user: user.notification_type == 'inbox')
+        inbox_users.write({"groups_id": [Command.link(inbox_group.id)]})
+        (self - inbox_users).write({"groups_id": [Command.unlink(inbox_group.id)]})
 
     # ------------------------------------------------------------
     # CRUD
diff --git a/addons/mail/tests/common.py b/addons/mail/tests/common.py
index fc8c4b7cc32..97a81e22f5f 100644
--- a/addons/mail/tests/common.py
+++ b/addons/mail/tests/common.py
@@ -27,8 +27,7 @@ from odoo.tools.translate import code_translations
 mail_new_test_user = partial(new_test_user, context={'mail_create_nolog': True,
                                                      'mail_create_nosubscribe': True,
                                                      'mail_notrack': True,
-                                                     'no_reset_password': True,
-                                                     'discuss_channel_nosubscribe': True})
+                                                     'no_reset_password': True})
 
 
 class MockEmail(common.BaseCase, MockSmtplibCase):
@@ -736,7 +735,6 @@ class MailCase(MockEmail):
                             ("UNKNOWN", "Unknown error")
     """
     _test_context = {
-        'discuss_channel_nosubscribe': True,
         'mail_create_nolog': True,
         'mail_create_nosubscribe': True,
         'mail_notrack': True,
diff --git a/addons/mail/tests/discuss/test_discuss_channel_member.py b/addons/mail/tests/discuss/test_discuss_channel_member.py
index 580f0032257..8a742fcc351 100644
--- a/addons/mail/tests/discuss/test_discuss_channel_member.py
+++ b/addons/mail/tests/discuss/test_discuss_channel_member.py
@@ -1,8 +1,8 @@
 # Part of Odoo. See LICENSE file for full copyright and licensing details.
 
-from odoo.addons.mail.tests.common import MailCommon, mail_new_test_user
+from odoo.addons.mail.tests.common import MailCommon
 from odoo.exceptions import AccessError, UserError, ValidationError
-from odoo.tests.common import tagged
+from odoo.tests.common import new_test_user, tagged
 
 
 @tagged("post_install", "-at_install")
@@ -20,19 +20,19 @@ class TestDiscussChannelMember(MailCommon):
             'model': cls.secret_group._name,
             'res_id': cls.secret_group.id,
         })
-        cls.user_1 = mail_new_test_user(
+        cls.user_1 = new_test_user(
             cls.env, login="user_1", name="User 1", groups="base.group_user,mail.secret_group"
         )
-        cls.user_2 = mail_new_test_user(
+        cls.user_2 = new_test_user(
             cls.env, login="user_2", name="User 2", groups="base.group_user,mail.secret_group"
         )
-        cls.user_3 = mail_new_test_user(
+        cls.user_3 = new_test_user(
             cls.env, login="user_3", name="User 3", groups="base.group_user,mail.secret_group"
         )
-        cls.user_portal = mail_new_test_user(
+        cls.user_portal = new_test_user(
             cls.env, login="user_portal", name="User Portal", groups="base.group_portal"
         )
-        cls.user_public = mail_new_test_user(
+        cls.user_public = new_test_user(
             cls.env, login="user_public", name="User Public", groups="base.group_public"
         )
 
@@ -75,7 +75,7 @@ class TestDiscussChannelMember(MailCommon):
             })
 
         # User 2 can not write on `discuss.channel.member` to join the group
-        channel_member = self.env['discuss.channel.member'].with_user(self.user_2).search([('partner_id', '=', self.user_2.partner_id.id)])[0]
+        channel_member = self.env['discuss.channel.member'].with_user(self.user_2).search([('is_self', '=', True)])[0]
         with self.assertRaises(AccessError):
             channel_member.channel_id = self.group.id
         with self.assertRaises(AccessError):