diff --git a/addons/project/security/project_security.xml b/addons/project/security/project_security.xml
index 6bc0c514544..02ce3a99fe4 100644
--- a/addons/project/security/project_security.xml
+++ b/addons/project/security/project_security.xml
@@ -82,10 +82,12 @@
         <field name="name">Project/Task: employees: follow required for follower-only projects</field>
         <field name="model_id" ref="model_project_task"/>
         <field name="domain_force">[
-        '|',
-            ('project_id.privacy_visibility', '!=', 'followers'),
             '|',
-                ('project_id.message_partner_ids', 'in', [user.partner_id.id]),
+                '&amp;',
+                    ('project_id', '!=', False),
+                    '|',
+                        ('project_id.privacy_visibility', '!=', 'followers'),
+                        ('project_id.message_partner_ids', 'in', [user.partner_id.id]),
                 '|',
                     ('message_partner_ids', 'in', [user.partner_id.id]),
                     # to subscribe check access to the record, follower is not enough at creation
diff --git a/addons/project/tests/test_access_rights.py b/addons/project/tests/test_access_rights.py
index ff1c29f69ed..d32f3349043 100644
--- a/addons/project/tests/test_access_rights.py
+++ b/addons/project/tests/test_access_rights.py
@@ -3,6 +3,7 @@
 
 from odoo.addons.mail.tests.common import mail_new_test_user
 from odoo.addons.project.tests.test_project_base import TestProjectCommon
+from odoo import Command
 from odoo.exceptions import AccessError, ValidationError
 from odoo.tests.common import users
 from odoo.tools import mute_logger
@@ -324,3 +325,63 @@ class TestPortalProject(TestProjectPortalCommon):
         # Do: project user can create a task without project
         self.assertRaises(AccessError, self.env['project.task'].with_user(self.user_projectuser).with_context({
             'mail_create_nolog': True}).create, {'name': 'Pigs task', 'project_id': pigs.id})
+
+
+class TestAccessRightsPrivateTask(TestAccessRights):
+
+    @classmethod
+    def setUpClass(cls):
+        super().setUpClass()
+        cls.private_task = cls.env['project.task'].create({'name': 'OdooBot Private Task'})
+
+    def setUp(self):
+        super().setUp()
+        self.project_user = mail_new_test_user(self.env, 'Project user', groups='project.group_project_user')
+
+    def create_private_task(self, name, with_user=None, **kwargs):
+        user = with_user or self.env.user
+        values = {'name': name, 'user_ids': [Command.set(user.ids)], **kwargs}
+        return self.env['project.task'].with_user(user).create(values)
+
+    @users('Internal user', 'Portal user')
+    def test_internal_cannot_crud_private_task(self):
+        with self.assertRaises(AccessError):
+            self.create_private_task('Private task')
+
+        with self.assertRaises(AccessError):
+            self.private_task.with_user(self.env.user).write({'name': 'Test write'})
+
+        with self.assertRaises(AccessError):
+            self.private_task.with_user(self.env.user).unlink()
+
+        with self.assertRaises(AccessError):
+            self.private_task.with_user(self.env.user).read(['name'])
+
+    @users('Project user')
+    def test_project_user_crud_own_private_task(self):
+        private_task = self.create_private_task('Private task')
+
+        private_task.with_user(self.env.user).write({'name': 'Test write'})
+        vals = private_task.with_user(self.env.user).read(['name'])
+        self.assertEqual(vals[0]['id'], private_task.id)
+        self.assertEqual(vals[0]['name'], private_task.name)
+
+    @users('Project user')
+    def test_project_user_cannot_create_private_task_for_another_user(self):
+        with self.assertRaises(AccessError):
+            self.create_private_task('test private for another user', self.env.user, user_ids=[Command.set(self.user_projectuser.ids)])
+
+    @users('Project user')
+    def test_project_user_cannot_write_private_task_of_another_user(self):
+        with self.assertRaises(AccessError):
+            self.private_task.with_user(self.env.user).write({'name': 'Test write'})
+
+    @users('Project user')
+    def test_project_user_cannot_read_private_task_of_another_user(self):
+        with self.assertRaises(AccessError):
+            self.private_task.with_user(self.env.user).read(['name'])
+
+    @users('Project user')
+    def test_project_user_cannot_unlink_private_task_of_another_user(self):
+        with self.assertRaises(AccessError):
+            self.private_task.with_user(self.env.user).unlink()
diff --git a/addons/sale_timesheet/tests/test_sale_service.py b/addons/sale_timesheet/tests/test_sale_service.py
index 907aafa030b..03303846f62 100644
--- a/addons/sale_timesheet/tests/test_sale_service.py
+++ b/addons/sale_timesheet/tests/test_sale_service.py
@@ -602,11 +602,12 @@ class TestSaleService(TestCommonSaleTimesheet):
             'gram': 0.0,
         }
 
+        project = self.project_global.copy({'tasks': False})
         Product = self.env['product.product']
         product_vals = {
             'type': 'service',
             'service_type': 'timesheet',
-            'project_id': self.project_global.id,
+            'project_id': project.id,
             'service_tracking': 'task_global_project',
         }
 
@@ -617,7 +618,6 @@ class TestSaleService(TestCommonSaleTimesheet):
             'order_id': self.sale_order.id,
         }
 
-        self.project_global.task_ids = False
         for uom_name in planned_hours_for_uom:
             uom_id = self.env.ref('uom.product_uom_%s' % uom_name)
 
@@ -637,7 +637,7 @@ class TestSaleService(TestCommonSaleTimesheet):
 
         self.sale_order.action_confirm()
 
-        tasks = self.project_global.task_ids
+        tasks = project.task_ids
         for task in tasks:
             self.assertEqual(task.planned_hours, planned_hours_for_uom[task.sale_line_id.name])