Transaction recorded (LUW with update records)

What causes this issue?

The LUW contains update records.

System Response

A CALL FUNCTION ... IN BACKGROUND TASK statement with update records
constitutes an LUW.
If one of the records cannot be updated, the system does not execute
the statement. The background records are executed only during the
post-update process. For this, use Transaction SM13.

Error message extract from SAP system. Copyright SAP SE.