sortable_column_headers plugin not sorting properly?

It appears the default sort direction is always sent to the query,
even if a different column is clicked to sort.

For example:

add_to_sortable_columns('search', :model => Status, :field => 'name',
:sort_direction => :desc)

that results in:

ORDER BY DESC,directories.updated_at DESC

Being sent everytime, even on the sorting of a different field altogether.

The default sort order is:

           :order => sortable_order('search',
                                            :model => Directory,
                                            :field => 'updated_at',
                                            :sort_direction => :desc

In other words, no matter what the default sort order is always sent
to the query, and in an un-observable order.