3125589 - Error: Unit of measure H does not correspond to base unit of measure when submitting time for contingent worker

When trying to submit time for a contingent worker, customer gets error: 

Unit of measure H does not correspond to base unit of measure

SAP S/4HANA Cloud

Unit of the purchase order is not H.

Change the Unit of the purchase order to H.

contingent worker, staffing, PDA , KBA , CA-TS-S4 , Cross Application Timesheet in S/4HANA , Problem