[Plugin: Shortcodes Pro] attributes_slug not working

Attribute slugs are not being populated with their values as specified in the shortcode settings. The content portion works, but the attribute_slug tag does not get replaced by a value.

Here is what I specified for my text attribute options
Third|third,Last|last

This is what I am using for the HTML code
<div class="%%attribute_slug%%">%%content%%</div>

But all I get in the generated page is
<div class="%%attribute_slug%%">sample text for column here.</div>

http://ww.wp.xz.cn/extend/plugins/shortcodes-pro/