I installed the latest version of the new theme: 1.7.1.1

This caused a fatal error on my shop page. The shop page is build with a grid-list referring to the shop items. Whenever I want to visit the shop page or the shop page on the CMS, I get the notification that a fatal error has occured:

Foutdetails
===========
Een fout van het type E_ERROR werd veroorzaakt op regelnummer 1108 van het bestand /customers/f/9/9/olivesandmore.nl/httpd.www/wp-content/plugins/bm-builder/include/templates/modules/module-grid.php. Foutmelding: Uncaught Error: Call to a member function is_on_sale() on null in /customers/f/9/9/olivesandmore.nl/httpd.www/wp-content/plugins/bm-builder/include/templates/modules/module-grid.php:1108
Stack trace:
#0 /customers/f/9/9/olivesandmore.nl/httpd.www/wp-content/plugins/bm-builder/include/templates/modules/module-grid.php(1476): ux_cb_module_grid_container(Array, ‘1575280311180’)
#1 /customers/f/9/9/olivesandmore.nl/httpd.www/wp-includes/class-wp-hook.php(289): ux_cb_module_grid_container(Array, ‘1575280311180’)
#2 /customers/f/9/9/olivesandmore.nl/httpd.www/wp-includes/plugin.php(212): WP_Hook->apply_filters(Array, Array)
#3 /customers/f/9/9/olivesandmore.nl/httpd.www/wp-content/plugins/bm-builder/include/classes/settings/fields.php(127): apply_filters(‘ux_cb_module_co…’, Array, ‘1575280311180’, false)
#4 /customers/f/9/9/olivesandmore.nl/httpd.www/wp-content/plugins/bm-builder/include/helpers/helpers_factory.php(478): UX_CB_Module_Fields->templates(Array, Array, false, false)
#5 /customers/f/9/9/olivesandmore.

I will (again!) have to revert to a back-up. But that means I cannot use the BM content builder anymore. So please I need a quick solution because I cannot afford the shop to be not running.