ai1ec posts don't stick

I am using a child theme of Twenty Eleven with the featured post slider running on the homepage. This uses the featured image from sticky posts in the slider.

I am also using All In One Events Calendar, which uses a custom post type for each event on the calendar. (The posts do have featured images set.)

I would like to make certain events posts sticky, and so I activated this plugin and selected the appropriate settings for the custom post type to be displayed on the home page. The check box does appear on the post page, but the post does not “stick” to the slider.

Is there something I’m missing?

(this if for https://www.skagitchildrensmuseum.net)

https://www.ads-software.com/extend/plugins/sticky-custom-post-types/