Workflow Internal Input Variable ifsBpaCurrentUserId is not working

I am trying to read the internal input variable ‘ifsBpaCurrentUserId’ in a workflow. The result is zero.
We are using IFSCloud 25R1 SU5.

Script:

var debugUserID = execution.getVariable('ifsBpaCurrentUserId');
var debugUserDirectoryID = execution.getVariable('ifsBpaCurrentUserDirectoryId');

// Set UserID
execution.setVariable('UserID', SingletonUser_Set[0].Identity);
execution.setVariable('debugUserID_', debugUserID );
execution.setVariable('debugUserDirectoryID_', debugUserDirectoryID);

Result:
 

Has anyone else encountered the same error? Is this a bug?