event_generate_quotation_from_registration/models/event_registration.py

@@ -37,7 +37,8 @@ class EventRegistration(models.Model):
                 else:
                     order_lines = self.env['sale.order.line'].search([
                         ('order_id','=',financier.quotation_id.id),
-                        ('product_id','=',financier.get_product_id())
+                        ('product_id','=',financier.get_product_id()),
+                        ('state', '!=', 'done'),
                     ])
                     if order_lines:
                         order_lines[0].price_unit = financier.amount