You are using the new feature 'Default Value Using Rules' however it is not working in some cases.
Key User(s) can now create ‘Value’ type Business Rules which returns a value. These ‘Value’ type Business Rules can be assigned to applicable fields in quick create screen.
SAP Cloud for customer.
This is the system expected behavior.
Below are the current limitations:
* Default Value Rule will override any other logic in place Ex: will override CLR, Extension Scenario , SDK Script Determination, Application logic etc.
* Applies only in Quick Create UI – Not applicable for backend/API calls.
* Cannot be applied to Object Value Selector Fields (Ex: Account Object Field) and Multi Value Fields.
* Cannot be applied to PSM fields.
* Key users should not use this feature on 'SAP standard defined read-only fields' as default rule can override read-only fields value.
* Simple defaulting shall work only if QC is opened from the OWL and may not work when launched from TI.
Default Value, Limitations Default Value, Default Value Using Rules. , KBA , AP-RC-UIF-FLX , Page Layout & Key User Configuration , Problem