Sort by Options field not working in $pages->find($selector)

[Toutouwai]

$results = $pages->find("template=my_template, sort=my_options_field.sort");

The above does not sort $results according to the sort order of the options field. Also, attempting to reverse the sort order with sort=-my_options_field.sort has no effect.

Sorting a page array works properly though.

$results->sort("my_options_field.sort");