Issue
Why is Business Services auto created by System User.
Release
Kingston and London
Cause
Service Mapping uses load balancers on a network to identify possible Business Services (candidates), the business services created by 'system' user would be a result of approving the candidates by choosing map your services option from the service mapping home page.
Resolution
It is recommend to review while approving the candidates by choosing map your services option from the service mapping home page to avoid creation of undesired business services by 'system' users.
For more information refer to product document:
https://docs.servicenow.com/csh?topicname=map-business-services-in-bulk.html&version=latest