[events-list] shortcode causes error message

The listing works but there is an error message above it.

Deprecated: preg_match(): Passing null to parameter #2 ($subject) of type string is deprecated in /home3/bvillart/public_html/wp-content/plugins/events-manager/classes/em-object.php on line 1407

The site is running php 8.1

The page I need help with: [log in to see the link]