diff --git a/addons/event/models/event.py b/addons/event/models/event.py
index a60e06842a8..51454b77de1 100644
--- a/addons/event/models/event.py
+++ b/addons/event/models/event.py
@@ -47,7 +47,7 @@ class event_event(models.Model):
         readonly=False, states={'done': [('readonly', True)]},
         oldname='type')
     color = fields.Integer('Kanban Color Index')
-    event_mail_ids = fields.One2many('event.mail', 'event_id', string='Mail Schedule', default=lambda self: self._default_event_mail_ids())
+    event_mail_ids = fields.One2many('event.mail', 'event_id', string='Mail Schedule', default=lambda self: self._default_event_mail_ids(), copy=True)
 
     @api.model
     def _default_event_mail_ids(self):
diff --git a/addons/website_event_questions/models/event.py b/addons/website_event_questions/models/event.py
index 77cdf75ada4..41cb2900585 100644
--- a/addons/website_event_questions/models/event.py
+++ b/addons/website_event_questions/models/event.py
@@ -7,7 +7,7 @@ class EventEvent(models.Model):
     """ Override Event model to add optional questions when buying tickets. """
     _inherit = 'event.event'
 
-    question_ids = fields.One2many('event.question', 'event_id', 'Questions')
+    question_ids = fields.One2many('event.question', 'event_id', 'Questions', copy=True)
     general_question_ids = fields.One2many('event.question', 'event_id', 'Questions',
                                            domain=[('is_individual', '=', False)])
     specific_question_ids = fields.One2many('event.question', 'event_id', 'Questions',
@@ -41,7 +41,7 @@ class EventQuestion(models.Model):
 
     title = fields.Char(required=True, translate=True)
     event_id = fields.Many2one('event.event', required=True, ondelete='cascade')
-    answer_ids = fields.One2many('event.answer', 'question_id', "Answers", required=True)
+    answer_ids = fields.One2many('event.answer', 'question_id', "Answers", required=True, copy=True)
     sequence = fields.Integer(default=10)
     is_individual = fields.Boolean('Ask each attendee',
                                    help="If True, this question will be asked for every attendee of a reservation. If "