About Pipeline Content and Referenced Process Errors
Generally, the error handler step in a business process receives the pipeline of the process when the error occurs. Special circumstances apply when an error occurs in a child referenced process.
When a process calls a child referenced process and the child process fails with an uncontrolled error (that is, the child process has no error handler), the status of the child process is set to Failed and the child process is waiting to be resubmitted.