Absence lasting less than one day for &1 on &2 ignored

What causes this issue?

An one-day absence without times exists for employee &V1& on &V2&.
Since the times are missing, the system cannot process the absence
further.

System Response

The absence is not taken into account when the personal shift plan of
employee &V1& is being contructed or when the order is being scheduled.

How to fix this error?

Enter the times for the absence.

Error message extract from SAP system. Copyright SAP SE.