There are various points in this spec where content is dynamically added to the DOM, but Capybara is jumping ahead to start interacting with it before it as actually finished loading.
This now shows that there is one consistent spec erroring, spec/features/admin/order_cycles/complex_editing_multiple_product_pages_spec.rb:
Capybara::ElementNotFound:
Unable to find visible checkbox "order_cycle_incoming_exchange_0_select_all_variants" that is not disabled