Billing documents are created with function modules in user-defined programs or other SAP applications. In billing, output determination is performed. The following symptoms may occur:
1. If you use collective billing (Transaction VF04 or VF06) to create and print several billing documents, the system only finds an output for the first billing document.
2. If output determination is also performed in the calling program of the billing function modules, then, when the billing function modules are processed, the system finds and processes output twice. Additional key words
Billing document, output, output determination, output control Cause and prerequisites
The problem is caused by a program error. Solution
https://service.sap.com/sap/support/notes/105241 (SAP Service marketplace login required)