diff --git a/addons/mail/models/mail_thread.py b/addons/mail/models/mail_thread.py
index eecb71308c1..8a7a77c5614 100644
--- a/addons/mail/models/mail_thread.py
+++ b/addons/mail/models/mail_thread.py
@@ -689,7 +689,7 @@ class MailThread(models.AbstractModel):
             view_title = _('View')
 
         default_groups = [
-            ('user', lambda partner: bool(partner.user_ids) and not any(user.share for user in partner.user_ids), {}),
+            ('user', lambda partner: bool(partner.user_ids) and any(not user.share for user in partner.user_ids), {}),
             ('portal', lambda partner: bool(partner.user_ids) and all(user.share for user in partner.user_ids), {
                 'has_button_access': False,
             }),
diff --git a/addons/project/models/project.py b/addons/project/models/project.py
index 6be83391fd3..c4121bb8b58 100644
--- a/addons/project/models/project.py
+++ b/addons/project/models/project.py
@@ -858,14 +858,19 @@ class Task(models.Model):
         groups = super(Task, self)._notify_get_groups(message, groups)
 
         self.ensure_one()
+
+        new_group = (
+            'group_project_user',
+            lambda partner: bool(partner.user_ids) and any(user.has_group('project.group_project_user') for user in partner.user_ids),
+            {},
+        )
+
         if not self.user_id and not self.stage_id.fold:
             take_action = self._notify_get_action_link('assign')
             project_actions = [{'url': take_action, 'title': _('I take it')}]
-            new_group = (
-                'group_project_user', lambda partner: bool(partner.user_ids) and any(user.has_group('project.group_project_user') for user in partner.user_ids), {
-                    'actions': project_actions,
-                })
-            groups = [new_group] + groups
+            new_group[2]['actions'] = project_actions
+
+        groups = [new_group] + groups
 
         for group_name, group_method, group_data in groups:
             if group_name == 'customer':