Field &1 is empty

What causes this issue?

It has been determined in the update of the billing program in module
ISU_CONFIRM_ERCH_EITR_FIELDS that field &v1& is not filled.

System Response

Billing was canceled because the data is inconsistent.

How to fix this error?

A program error has occurred; contact SAP.

Error message extract from SAP system. Copyright SAP SE.