diff --git a/addons/crm/models/crm_lead.py b/addons/crm/models/crm_lead.py
index 114d8f0842e..f0687a0dc08 100644
--- a/addons/crm/models/crm_lead.py
+++ b/addons/crm/models/crm_lead.py
@@ -1669,21 +1669,21 @@ class Lead(models.Model):
         """ Handle salesman recipients that can convert leads into opportunities
         and set opportunities as won / lost. """
         groups = super(Lead, self)._notify_get_groups(msg_vals=msg_vals)
-        msg_vals = msg_vals or {}
+        local_msg_vals = dict(msg_vals or {})
 
         self.ensure_one()
         if self.type == 'lead':
-            convert_action = self._notify_get_action_link('controller', controller='/lead/convert', **msg_vals)
+            convert_action = self._notify_get_action_link('controller', controller='/lead/convert', **local_msg_vals)
             salesman_actions = [{'url': convert_action, 'title': _('Convert to opportunity')}]
         else:
-            won_action = self._notify_get_action_link('controller', controller='/lead/case_mark_won', **msg_vals)
-            lost_action = self._notify_get_action_link('controller', controller='/lead/case_mark_lost', **msg_vals)
+            won_action = self._notify_get_action_link('controller', controller='/lead/case_mark_won', **local_msg_vals)
+            lost_action = self._notify_get_action_link('controller', controller='/lead/case_mark_lost', **local_msg_vals)
             salesman_actions = [
                 {'url': won_action, 'title': _('Won')},
                 {'url': lost_action, 'title': _('Lost')}]
 
         if self.team_id:
-            custom_params = dict(msg_vals, res_id=self.team_id.id, model=self.team_id._name)
+            custom_params = dict(local_msg_vals, res_id=self.team_id.id, model=self.team_id._name)
             salesman_actions.append({
                 'url': self._notify_get_action_link('view', **custom_params),
                 'title': _('Sales Team Settings')
diff --git a/addons/hr_holidays/models/hr_leave.py b/addons/hr_holidays/models/hr_leave.py
index 29508c37a0a..eb9936a4732 100644
--- a/addons/hr_holidays/models/hr_leave.py
+++ b/addons/hr_holidays/models/hr_leave.py
@@ -1221,15 +1221,15 @@ class HolidaysRequest(models.Model):
         """ Handle HR users and officers recipients that can validate or refuse holidays
         directly from email. """
         groups = super(HolidaysRequest, self)._notify_get_groups(msg_vals=msg_vals)
-        msg_vals = msg_vals or {}
+        local_msg_vals = dict(msg_vals or {})
 
         self.ensure_one()
         hr_actions = []
         if self.state == 'confirm':
-            app_action = self._notify_get_action_link('controller', controller='/leave/validate', **msg_vals)
+            app_action = self._notify_get_action_link('controller', controller='/leave/validate', **local_msg_vals)
             hr_actions += [{'url': app_action, 'title': _('Approve')}]
         if self.state in ['confirm', 'validate', 'validate1']:
-            ref_action = self._notify_get_action_link('controller', controller='/leave/refuse', **msg_vals)
+            ref_action = self._notify_get_action_link('controller', controller='/leave/refuse', **local_msg_vals)
             hr_actions += [{'url': ref_action, 'title': _('Refuse')}]
 
         holiday_user_group_id = self.env.ref('hr_holidays.group_hr_holidays_user').id
diff --git a/addons/hr_holidays/models/hr_leave_allocation.py b/addons/hr_holidays/models/hr_leave_allocation.py
index b5e007efc98..8650f18310e 100644
--- a/addons/hr_holidays/models/hr_leave_allocation.py
+++ b/addons/hr_holidays/models/hr_leave_allocation.py
@@ -670,15 +670,15 @@ class HolidaysAllocation(models.Model):
         """ Handle HR users and officers recipients that can validate or refuse holidays
         directly from email. """
         groups = super(HolidaysAllocation, self)._notify_get_groups(msg_vals=msg_vals)
-        msg_vals = msg_vals or {}
+        local_msg_vals = dict(msg_vals or {})
 
         self.ensure_one()
         hr_actions = []
         if self.state == 'confirm':
-            app_action = self._notify_get_action_link('controller', controller='/allocation/validate', **msg_vals)
+            app_action = self._notify_get_action_link('controller', controller='/allocation/validate', **local_msg_vals)
             hr_actions += [{'url': app_action, 'title': _('Approve')}]
         if self.state in ['confirm', 'validate', 'validate1']:
-            ref_action = self._notify_get_action_link('controller', controller='/allocation/refuse', **msg_vals)
+            ref_action = self._notify_get_action_link('controller', controller='/allocation/refuse', **local_msg_vals)
             hr_actions += [{'url': ref_action, 'title': _('Refuse')}]
 
         holiday_user_group_id = self.env.ref('hr_holidays.group_hr_holidays_user').id
diff --git a/addons/portal/models/portal_mixin.py b/addons/portal/models/portal_mixin.py
index 8b8b25f610f..d2e9e83f094 100644
--- a/addons/portal/models/portal_mixin.py
+++ b/addons/portal/models/portal_mixin.py
@@ -63,13 +63,13 @@ class PortalMixin(models.AbstractModel):
     def _notify_get_groups(self, msg_vals=None):
         access_token = self._portal_ensure_token()
         groups = super(PortalMixin, self)._notify_get_groups(msg_vals=msg_vals)
-        msg_vals = msg_vals or {}
+        local_msg_vals = dict(msg_vals or {})
 
         if access_token and 'partner_id' in self._fields and self['partner_id']:
             customer = self['partner_id']
-            msg_vals['access_token'] = self.access_token
-            msg_vals.update(customer.signup_get_auth_param()[customer.id])
-            access_link = self._notify_get_action_link('view', **msg_vals)
+            local_msg_vals['access_token'] = self.access_token
+            local_msg_vals.update(customer.signup_get_auth_param()[customer.id])
+            access_link = self._notify_get_action_link('view', **local_msg_vals)
 
             new_group = [
                 ('portal_customer', lambda pdata: pdata['id'] == customer.id, {
diff --git a/addons/project/models/project.py b/addons/project/models/project.py
index 988d70842f6..05807fd78b1 100644
--- a/addons/project/models/project.py
+++ b/addons/project/models/project.py
@@ -1212,13 +1212,13 @@ class Task(models.Model):
         access button to portal users and portal customers. If they are notified
         they should probably have access to the document. """
         groups = super(Task, self)._notify_get_groups(msg_vals=msg_vals)
-        msg_vals = msg_vals or {}
+        local_msg_vals = dict(msg_vals or {})
         self.ensure_one()
 
         project_user_group_id = self.env.ref('project.group_project_user').id
         new_group = ('group_project_user', lambda pdata: pdata['type'] == 'user' and project_user_group_id in pdata['groups'], {})
         if not self.user_id and not self.stage_id.fold:
-            take_action = self._notify_get_action_link('assign', **msg_vals)
+            take_action = self._notify_get_action_link('assign', **local_msg_vals)
             project_actions = [{'url': take_action, 'title': _('I take it')}]
             new_group[2]['actions'] = project_actions
         groups = [new_group] + groups