How do I customize hierarchical breadcrumbs?
In D8 the hierarchy of breadcrumbs is by default path based, so you have to change the path for the second level from /service1 to /services/service1

Or install a module to build the hierarchy based on menus or taxonomy terms:

https://www.drupal.org/project/menu_breadcrumb
https://www.drupal.org/project/taxonomy_breadcrumb