3331372 - Error creating Service Entry Sheets from timesheet entries

As a contingent worker or a line manager you post working hours against a purchase order using the APP 'Manage My Timesheet' or 'Notify Missing Times' respectively. 
You expect the system to automatically generate a service entry sheet but when you check the job log via the APP 'Monitor Service Entry Sheet Generation Log' you find unexpected errors like MM_PUR_SES042 or MM_PUR_SES057.

SAP S/4Hana Cloud - All Versions 

1) Post your working hours via APP 'Manage My Timesheet'
2) Check the the APP 'Monitor Service Entry Sheet Generation Log' Errors such as these below are found in the job log  
'Product group XX differs from the product group of the PO item XX' (MM_PUR_SES042)
'The service XX differs from the service of the purchase order item XX' (MM_PUR_SES057). 

Unauthorised user or master data issue.

When the system tries to generate a service entry sheet from a timesheet it tries to copy the purchase order item data over to the service entry sheet. 
In the copy, the system checks the authorisation of the user, the 'GR based IV' flag is set on the PO item and that the deletion indicator is not set. If 
all these are valid then the PO item data is transferred to the new SES item. If there is a failure not all of the PO item will be transferred leading to such errors.  

** Note regarding error MM_PUR_SES057.
If posting a service entry sheet via API or from an external application like field glass for example. 
This error is raised when the system compares the service material from the reference purchase order with the SERVICE value passed in via the payload. 
The SERVICE field of the payload must match the material ID of the reference purchase order. 

1) Check the user has full authorisation for the Company code, Purchase Organisation, Purchasing group and plant in the reference purchase order. 
2) Check the reference purchase order item is not marked for deletion 
3) Check the reference purchase order item has the GR based IV flag set 

2686576

WEBRE, CL_DET_SES_ITEM_COPY_FROM_PO, MM_SES_EKO, MM_PUR_SES042, MM_PUR_SES057 , KBA , MM-PUR-SVC-SES , Service Entry Sheet for Service Procurement , Problem