diff --git a/src/pretix/api/webhooks.py b/src/pretix/api/webhooks.py
index f1a5240348..e727c80884 100644
--- a/src/pretix/api/webhooks.py
+++ b/src/pretix/api/webhooks.py
@@ -102,6 +102,7 @@ class ParametrizedOrderPositionWebhookEvent(ParametrizedOrderWebhookEvent):
         d['orderposition_positionid'] = logentry.parsed_data.get('positionid')
         d['checkin_list'] = logentry.parsed_data.get('list')
         d['first_checkin'] = logentry.parsed_data.get('first_checkin')
+        return d
 
 
 @receiver(register_webhook_events, dispatch_uid="base_register_default_webhook_events")