Event Ordering using Sort-Order

I'm trying to order my event posts so that they are ascending. Although the events display, the order won't change from asc to desc. This one has me stumped! The same code is working perfectly on my other sites, so any ideas would be welcome.

perch_events_custom(array(
   'filter'            => 'eventDateTime',
   'match'         => 'lt',
   'value'           => date('Y-m-d'),
   'sort'             => 'eventDateTime',
   'sort-order'    => 'desc',
   template'       => 'listing/custom-listing-day.html'
));