Specify only one task with category "data collection" in task group &

What causes this issue?

<DS:GLOS.task_group>Task group</> &v1& has more than one
<DS:GLOS.task>task</> of the category 'Data collection'. Only one task
is needed for this category.

System Response

Processing terminated

How to fix this error?

Define a maximum of only one task for collecting data in each task
group.

Error message extract from SAP system. Copyright SAP SE.