Parallel processing: System error when receiving task results

What causes this issue?

In parallel processing, the results of a task (processing package)
could not be received after the task was terminated. The system message
is as follows:
&v1&

System Response

The materials of this task were not marked or released.

How to fix this error?

Carry out marking or release at a later time. If the error recurs,
proceed with marking or release without parallel processing.

Error message extract from SAP system. Copyright SAP SE.