Homepage now displays 2-columns instead of one

Replies: 0

The linked site uses a child theme of Storefront.

Within the last week, the homepage of this site stopped displaying as a single column and began displaying two columns.

Looking at the page from the administration dashboard, I see that the TEMPLATES dropdown is not appearing. So the template cannot be be set back to HOMEPAGE.

Going to APPEARANCE > THEMES, I get the following message:

Broken Themes
The following themes are installed but incomplete.

Name		
Storefront Child Theme URI: http://www.woothemes.com/storefront Description: Storefront Child Theme Author: WooThemes Author URI: http://www.woothemes.com Template: storefront Version: 1.0.0 License: GNU General Public License v2 or later License URI: http://www.gnu.org/licenses/gpl-2.0.html Tags: light, dark, two-columns, right-sidebar, responsive-layout, accessibility-ready Text Domain: storefront-child

Description			
Template is missing. Standalone themes need to have a index.php template file. Child themes need to have a Template header in the style.css stylesheet.

(I note that TEMPLATE: STOREFRONT appears at the beginning of the child theme’s STYLE.CSS file.)

My other site, which also uses a STOREFRONT child theme, does not display this behavior.

This site uses:
STOREFRONT 3.7.0
WORDPRESS 5.7.2
WOOCOMMERCE 5.4.1