In database, the column type of pxCreateOperator in dbo.pr_operators is defined as varchar(128) and hence any space characters may also be allowed in the operator. But the pzInsKey of operator record is formed as ' DATA-ADMIN-OPERATOR-ID operatorid ' eg: (DATA-ADMIN-OPERATOR-ID ADMINISTRATOR@PEGA.COM)
If additional space is given while creation, the format of pzInsKey also gets changed, which may lead to some discrepancies. So the best practice may be is to avoid space , in the OperatorID. You can always use the short description field to have your custom name .