We have Elastisearch enabled on our site and use the Jetpack search filter widget on the sidebar of our search results page. This works fine in Jetpack 5.8.

After upgrading our site to Jetpack 5.9, the Jetpack search widget seems to have disappeared. It is not in the widgets list under appearance. It is not in the customizer widget list. And it does not render on the site. The only search widget that appears is the default WordPress search box, not the special Jetpack one.

The debug log gives this error as well: Undefined index: jetpack-search-filters-3 in /var/www/geekwire.com/wp-includes/widgets.php on line 813

Rolling back to 5.8 solves this issue.