We've noticed that if the JIRA Issue/Filter macro is configured to show "standard" user picker fields (E.g. "Assignee", "Reporter") then it shows the friendly username (E.g. "Andrew Pane") but if we add custom fields of type "User Picker (single user)" then this macro shows the login name (E.g. "andrew.pane"):

Does anyone know if there is a way to make it consistent, one way or another?
Thanks,
Andrew