Symptom
API "Workforce Timesheet" allows the employees to book time on WBS elements on which they are not staffed.
Environment
SAP S/4HANA Cloud
Cause
API validations are lesser in number in respect to the Manage My Timesheet app validations. In certain instances, the API validations might skip the app validations.
In the Manage My Timesheet app, posting of time entries will not be allowed if the Restrict Unstaffed Posting switch is on in the Plan Customer Projects app. An error message will be displayed on the UI. However, time entries for the unstaffed project can be posted using the API call.
Resolution
In order to avoid unstaffed posting through API, you can enable additional custom validations before saving a time entry, by using BADI HCM: Timesheet Validations (HCM_CATS_V1_TS_VALIDATION).
Check below help document.
See Also
SAP Help Documentation -- Workforce Timesheet
Keywords
API "Workforce Timesheet", unstaff, manage my timesheet, Restrict unstaffed posting, SAP S/4hana Cloud, CA-TS-S4. , KBA , CA-TS-S4 , Cross Application Timesheet in S/4HANA , Problem