Smart Query Hidden Field appearing in Export

I've created some Smart Queries in BBCRM and in doing so have hidden some fields in the ‘Set Save Options’ tab of the query editor. These are hidden when viewing the output in Smart Query Search, but when you export the results of the query (again still in Smarty Query Search) the hidden fields are included in the export.

Can anyone help explain why this is, as surely if you have it hidden it shouldn't be included in the export? Is this a bug? I can't just delete the field from the query as in some instances they are the primary key but we just want it hidden to avoid confusion with another field.