I found solution.
if i have post endpoint with populate query param “blabla/api/jobs?populate=*” then webhook has relation value.
But i use post endpoint without populate query param then webhook has no relation value.
Post Endpoint For Relation Value: {{baseUrl}}/strapicms/api/jobs?populate=*
Post Endpoint For No Relation Value: {{baseUrl}}/strapicms/api/jobs