diff --git a/addons/event_sale/models/event_registration.py b/addons/event_sale/models/event_registration.py
index 9300d610790..a17821cdc1c 100644
--- a/addons/event_sale/models/event_registration.py
+++ b/addons/event_sale/models/event_registration.py
@@ -26,19 +26,18 @@ class EventRegistration(models.Model):
 
     @api.depends('sale_order_id.state', 'sale_order_id.currency_id', 'sale_order_line_id.price_total')
     def _compute_registration_status(self):
-        self.filtered(lambda reg: not reg.state).state = 'draft'
         for so_line, registrations in self.grouped('sale_order_line_id').items():
             cancelled_so_registrations = registrations.filtered(lambda reg: reg.sale_order_id.state == 'cancel')
             cancelled_so_registrations.state = 'cancel'
             cancelled_registrations = cancelled_so_registrations | registrations.filtered(lambda reg: reg.state == 'cancel')
             if not so_line or float_is_zero(so_line.price_total, precision_digits=so_line.currency_id.rounding):
                 registrations.sale_status = 'free'
-                registrations.filtered(lambda reg: reg.state == 'draft').write({"state": "open"})
+                registrations.filtered(lambda reg: not reg.state or reg.state == 'draft').state = "open"
             else:
                 sold_registrations = registrations.filtered(lambda reg: reg.sale_order_id.state == 'sale') - cancelled_registrations
                 sold_registrations.sale_status = 'sold'
                 (registrations - sold_registrations).sale_status = 'to_pay'
-                sold_registrations.filtered(lambda reg: reg.state in {'draft', 'cancel'}).write({"state": "open"})
+                sold_registrations.filtered(lambda reg: not reg.state or reg.state in {'draft', 'cancel'}).state = "open"
                 (registrations - sold_registrations - cancelled_registrations).state = 'draft'
 
     @api.depends('sale_order_id')