Problem

When beforeSend returns a non-object (e.g. true, undefined, or omits return), that value was used as payload and sent to the collector. The backend then stored it as-is (e.g. payload: true in MongoDB), which led to:

• GraphQL: Cannot return null for non-nullable field EventPayload.title
• Frontend: TypeError: can't access property "event", l is null on project overview

Common mistakes:

• beforeSend: (e) => true (meant “allow”, but overwrites payload)
• beforeSend: (e) => { console.log(e); } (no return → undefined as payload)

Solution

Validate the return value of beforeSend and only use it when it’s a valid event object: