I believe I found an error in the NextGEN Monoslideshow code that prevents the plugin from obeying the setting (checkbox) for Randomize/Shuffle in the WP admin under Gallery > Monoslideshow...
File: xml.php
Line: 25
Original: $randomize = ($options['<strong>delay</strong>']) ? 'true' : 'false';
Fixed: $randomize = ($options['<strong>randomize</strong>']) ? 'true' : 'false';