Billing order deleted for contract &1 with scheduled billing date &2

What causes this issue?

This is a success message indicating that the billing order for
contract &v1& with scheduled billing date &v2& has been deleted.

System Response

The message is displayed in FM ISU_BILLING_UPDATE after FM
ISU_S_TRIGGER_DELETE has run successfully.

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Error message extract from SAP system. Copyright SAP SE.