Example: There was an error when modifying a Customers list, element "8000005F-1179498882". QuickBooks error message: This customer already has job information. To add a new job, the customer's current job information must be moved into its own job.
The parent you are attempting to add the sub customer to already has job info in QuickBooks.
Find the customer record in QuickBooks that is being referenced in the alert. Clear the job info or add it as a job attached to the parent.