David Plaut is looking for the root cause:
A SQL Server Agent job can start other jobs. Writing jobs this way makes it easy to compartmentalize jobs: start a “child” job only when the “parent” reaches a certain step. Finding these steps can be challenging. There is no field or property in sysjobs or its associated tables to help find child jobs.
Imagine this situation: Job B has started, and you don’t know why. You examine Job B, and it has no schedule. What started Job B?
Read on to learn how you can track down jobs that start other jobs, as well as a recursive lineage of who’s starting whom.