Uncaught TypeError: Cannot read properties of undefined (reading 'settings')

It's because after an attribute has been clicked (in 1 product to multiple variations model),
Drupal.views.instances object becomes undefined in facets-views-ajax.js.

Fast workaround in facets-views-ajax.js is

var views_arguments = Drupal.Views.parseViewArgs(href, 'search');
+ if (Object.keys(Drupal.views.instances).length === 0) { // if you changed the attributes in a product with several variations, the facet cannot be selected, therefore
+      window.location.reload();
+      return;
+    }