When using this email template in a workflow, ensure that the “requesterDisplayName” argument is included in the workflow step. This value can be obtained from the “requester”.
Add the below argument to workflow step and check the email.
<Arg name="requesterDisplayName">
<Script>
<Source>
import sailpoint.object.Identity;
Identity id=context.getObjectByName(Identity.class,requester);
if (id != null){
return id.getDisplayName();
}
</Source>
</Script>
</Arg>