Total Upkeep Uncaught Type Error Array Search

Hi,

today I received a mail info that total upkeep produced an error:

Uncaught TypeError: array_search(): Argument #2 ($haystack) must be of type array, false given in /var/www/vhosts/<hostname>/httpdocs/wp-content/plugins/boldgrid-backup/admin/class-boldgrid-backup-admin-cron.php:651

Stack trace:

#0 /var/www/vhosts/<hostname>/httpdocs/wp-content/plugins/boldgrid-backup/admin/class-boldgrid-backup-admin-cron.php(651): array_search('# Total Upkeep ...', false, true)

#1 /var/www/vhosts/<hostname>/httpdocs/wp-content/plugins/boldgrid-backup/admin/class-boldgrid-backup-admin-test.php(434): Boldgrid_Backup_Admin_Cron->entry_delete('# Total Upkeep ...')

#2 /var/www/vhosts/<hostname>/httpdocs/wp-content/plugins/boldgrid-backup/admin/class-boldgrid-backup-admin-scheduler.php(102): Boldgrid_Backup_Admin_Test->is_crontab_available()

#3 /var/www/vhosts/<hostname>/httpdocs/wp-content/plugins/boldgrid-backup/admin/class-boldgrid-backup-admin-scheduler.php(69): Boldgrid_Backup_Admin_Scheduler->get_available()

#4 /var/www/vhosts/<hostname>/httpdocs/wp-content/plugins/boldgrid-backup/admin/class-boldgrid-backup-admin-cron.php(1573): Boldgrid_Backup_Admin_Scheduler->get()

#5 /var/www/vhosts/<hostname>/httpdocs/wp-includes/class-wp-hook.php(341): Boldgrid_Backup_Admin_Cron->upgrade_crontab_entries('')

#6 /var/www/vhosts/<hostname>/httpdocs/wp-includes/class-wp-hook.php(365): WP_Hook->apply_filters(NULL, Array)

#7 /var/www/vhosts/<hostname>/httpdocs/wp-includes/plugin.php(522): WP_Hook->do_action(Array)

#8 /var/www/vhosts/<hostname>/httpdocs/wp-admin/admin-ajax.php(45): do_action('admin_init')

#9 {main}
  thrown


WordPress-Version 7.0.3
Aktive Theme: Customizr (Version 4.4.24) 
Plugin: Total Upkeep (Version 1.17.4) 
PHP-Version 8.3.33

What does it tell me and what should I do with it?
Best regards
Robert

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